diff --git a/dom/webauthn/WebAuthnManager.cpp b/dom/webauthn/WebAuthnManager.cpp
index ad9d746af05a..3d9d3015a447 100644
--- a/dom/webauthn/WebAuthnManager.cpp
+++ b/dom/webauthn/WebAuthnManager.cpp
@@ -258,7 +258,7 @@ already_AddRefed<Promise> WebAuthnManager::MakeCredential(
   CryptoBuffer userId;
   userId.Assign(aOptions.mUser.mId);
   if (userId.Length() > 64) {
-    promise->MaybeReject(NS_ERROR_DOM_TYPE_ERR);
+    promise->MaybeRejectWithTypeError(u"user.id is too long");
     return promise.forget();
   }
 
diff --git a/testing/web-platform/meta/webauthn/createcredential-badargs-user.https.html.ini b/testing/web-platform/meta/webauthn/createcredential-badargs-user.https.html.ini
deleted file mode 100644
index ca80a23ea164..000000000000
--- a/testing/web-platform/meta/webauthn/createcredential-badargs-user.https.html.ini
+++ /dev/null
@@ -1,180 +0,0 @@
-[createcredential-badargs-user.https.html]
-  disabled: https://bugzilla.mozilla.org/show_bug.cgi?id=1546662
-  expected:
-    if os == "android" and not e10s: OK
-    TIMEOUT
-  [Bad user: id is empty ArrayBuffer]
-    expected:
-      if os == "android" and not e10s: FAIL
-      if debug and webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): FAIL
-      if debug and webrender and e10s and (os == "win") and (version == "10.0.17134") and (processor == "x86_64") and (bits == 64): FAIL
-      if debug and not webrender and e10s and (os == "win") and (version == "10.0.17134") and (processor == "x86_64") and (bits == 64): FAIL
-      if debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): FAIL
-      if debug and not webrender and not e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86") and (bits == 32): FAIL
-      if debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86") and (bits == 32): FAIL
-      if debug and not webrender and e10s and (os == "win") and (version == "6.1.7601") and (processor == "x86") and (bits == 32): FAIL
-      if not debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): FAIL
-      TIMEOUT
-
-  [Bad user: ArrayBuffer id is too long (65 bytes)]
-    expected:
-      if os == "android" and not e10s: PASS
-      if debug and webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): PASS
-      if debug and webrender and e10s and (os == "win") and (version == "10.0.17134") and (processor == "x86_64") and (bits == 64): PASS
-      if debug and not webrender and e10s and (os == "win") and (version == "10.0.17134") and (processor == "x86_64") and (bits == 64): PASS
-      if debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): PASS
-      if debug and not webrender and not e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86") and (bits == 32): PASS
-      if debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86") and (bits == 32): PASS
-      if debug and not webrender and e10s and (os == "win") and (version == "6.1.7601") and (processor == "x86") and (bits == 32): PASS
-      if not debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): PASS
-      NOTRUN
-
-  [Bad user: Int16Array id is too long (66 bytes)]
-    expected:
-      if os == "android" and not e10s: PASS
-      if debug and webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): PASS
-      if debug and webrender and e10s and (os == "win") and (version == "10.0.17134") and (processor == "x86_64") and (bits == 64): PASS
-      if debug and not webrender and e10s and (os == "win") and (version == "10.0.17134") and (processor == "x86_64") and (bits == 64): PASS
-      if debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): PASS
-      if debug and not webrender and not e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86") and (bits == 32): PASS
-      if debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86") and (bits == 32): PASS
-      if debug and not webrender and e10s and (os == "win") and (version == "6.1.7601") and (processor == "x86") and (bits == 32): PASS
-      if not debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): PASS
-      NOTRUN
-
-  [Bad user: Int32Array id is too long (68 bytes)]
-    expected:
-      if os == "android" and not e10s: PASS
-      if debug and webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): PASS
-      if debug and webrender and e10s and (os == "win") and (version == "10.0.17134") and (processor == "x86_64") and (bits == 64): PASS
-      if debug and not webrender and e10s and (os == "win") and (version == "10.0.17134") and (processor == "x86_64") and (bits == 64): PASS
-      if debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): PASS
-      if debug and not webrender and not e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86") and (bits == 32): PASS
-      if debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86") and (bits == 32): PASS
-      if debug and not webrender and e10s and (os == "win") and (version == "6.1.7601") and (processor == "x86") and (bits == 32): PASS
-      if not debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): PASS
-      NOTRUN
-
-  [Bad user: Float32Array id is too long (68 bytes)]
-    expected:
-      if os == "android" and not e10s: PASS
-      if debug and webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): PASS
-      if debug and webrender and e10s and (os == "win") and (version == "10.0.17134") and (processor == "x86_64") and (bits == 64): PASS
-      if debug and not webrender and e10s and (os == "win") and (version == "10.0.17134") and (processor == "x86_64") and (bits == 64): PASS
-      if debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): PASS
-      if debug and not webrender and not e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86") and (bits == 32): PASS
-      if debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86") and (bits == 32): PASS
-      if debug and not webrender and e10s and (os == "win") and (version == "6.1.7601") and (processor == "x86") and (bits == 32): PASS
-      if not debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): PASS
-      NOTRUN
-
-  [Bad user: Float64Array id is too long (72 bytes)]
-    expected:
-      if os == "android" and not e10s: PASS
-      if debug and webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): PASS
-      if debug and webrender and e10s and (os == "win") and (version == "10.0.17134") and (processor == "x86_64") and (bits == 64): PASS
-      if debug and not webrender and e10s and (os == "win") and (version == "10.0.17134") and (processor == "x86_64") and (bits == 64): PASS
-      if debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): PASS
-      if debug and not webrender and not e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86") and (bits == 32): PASS
-      if debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86") and (bits == 32): PASS
-      if debug and not webrender and e10s and (os == "win") and (version == "6.1.7601") and (processor == "x86") and (bits == 32): PASS
-      if not debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): PASS
-      NOTRUN
-
-  [Bad user: id is too long (65 bytes)]
-    expected:
-      if os == "android" and not e10s: PASS
-      if debug and webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): PASS
-      if debug and webrender and e10s and (os == "win") and (version == "10.0.17134") and (processor == "x86_64") and (bits == 64): PASS
-      if debug and not webrender and e10s and (os == "win") and (version == "10.0.17134") and (processor == "x86_64") and (bits == 64): PASS
-      if debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): PASS
-      if debug and not webrender and not e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86") and (bits == 32): PASS
-      if debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86") and (bits == 32): PASS
-      if debug and not webrender and e10s and (os == "win") and (version == "6.1.7601") and (processor == "x86") and (bits == 32): PASS
-      if not debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): PASS
-      NOTRUN
-
-  [user missing name]
-    expected:
-      if os == "android" and not e10s: PASS
-      if debug and webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): PASS
-      if debug and webrender and e10s and (os == "win") and (version == "10.0.17134") and (processor == "x86_64") and (bits == 64): PASS
-      if debug and not webrender and e10s and (os == "win") and (version == "10.0.17134") and (processor == "x86_64") and (bits == 64): PASS
-      if debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): PASS
-      if debug and not webrender and not e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86") and (bits == 32): PASS
-      if debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86") and (bits == 32): PASS
-      if debug and not webrender and e10s and (os == "win") and (version == "6.1.7601") and (processor == "x86") and (bits == 32): PASS
-      if not debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): PASS
-      NOTRUN
-
-  [Bad user: name is object]
-    expected:
-      if os == "android" and not e10s: FAIL
-      if debug and webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): FAIL
-      if debug and webrender and e10s and (os == "win") and (version == "10.0.17134") and (processor == "x86_64") and (bits == 64): FAIL
-      if debug and not webrender and e10s and (os == "win") and (version == "10.0.17134") and (processor == "x86_64") and (bits == 64): FAIL
-      if debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): FAIL
-      if debug and not webrender and not e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86") and (bits == 32): FAIL
-      if debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86") and (bits == 32): FAIL
-      if debug and not webrender and e10s and (os == "win") and (version == "6.1.7601") and (processor == "x86") and (bits == 32): FAIL
-      if not debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): FAIL
-      NOTRUN
-
-  [Bad user: name is null]
-    expected:
-      if os == "android" and not e10s: FAIL
-      if debug and webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): TIMEOUT
-      if debug and webrender and e10s and (os == "win") and (version == "10.0.17134") and (processor == "x86_64") and (bits == 64): TIMEOUT
-      if debug and not webrender and e10s and (os == "win") and (version == "10.0.17134") and (processor == "x86_64") and (bits == 64): TIMEOUT
-      if debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): TIMEOUT
-      if debug and not webrender and not e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86") and (bits == 32): TIMEOUT
-      if debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86") and (bits == 32): TIMEOUT
-      if debug and not webrender and e10s and (os == "win") and (version == "6.1.7601") and (processor == "x86") and (bits == 32): TIMEOUT
-      if not debug and not webrender and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): TIMEOUT
-      NOTRUN
-
-  [Bad user: name is empty String]
-    expected:
-      if os == "android" and not e10s: FAIL
-      NOTRUN
-
-  [Bad user: icon is object]
-    expected:
-      if os == "android" and not e10s: FAIL
-      NOTRUN
-
-  [Bad user: icon is null]
-    expected:
-      if os == "android" and not e10s: FAIL
-      NOTRUN
-
-  [Bad user: icon is empty String]
-    expected:
-      if os == "android" and not e10s: FAIL
-      NOTRUN
-
-  [Bad user: displayName is undefined]
-    expected:
-      if os == "android" and not e10s: PASS
-      NOTRUN
-
-  [Bad user: displayName is object]
-    expected:
-      if os == "android" and not e10s: FAIL
-      NOTRUN
-
-  [Bad user: displayName is null]
-    expected:
-      if os == "android" and not e10s: FAIL
-      NOTRUN
-
-  [Bad user: displayName is empty String]
-    expected:
-      if os == "android" and not e10s: FAIL
-      NOTRUN
-
-  [Bad user: icon is insecure]
-    expected:
-      if os == "android" and not e10s: FAIL
-      NOTRUN
-
diff --git a/testing/web-platform/tests/webauthn/createcredential-badargs-user.https.html b/testing/web-platform/tests/webauthn/createcredential-badargs-user.https.html
index 6bcd90ff8f82..070a5c77dea2 100644
--- a/testing/web-platform/tests/webauthn/createcredential-badargs-user.https.html
+++ b/testing/web-platform/tests/webauthn/createcredential-badargs-user.https.html
@@ -23,7 +23,6 @@ standardSetup(function() {
     new CreateCredentialsTest("options.publicKey.user.id", null).runTest("Bad user: id is null", TypeError);
     new CreateCredentialsTest("options.publicKey.user.id", "").runTest("Bad user: id is empty String", TypeError);
     new CreateCredentialsTest("options.publicKey.user.id", new Array()).runTest("Bad user: id is empty Array", TypeError);
-    new CreateCredentialsTest("options.publicKey.user.id", new ArrayBuffer(0)).runTest("Bad user: id is empty ArrayBuffer", TypeError);
     new CreateCredentialsTest("options.publicKey.user.id", new ArrayBuffer(65)).runTest("Bad user: ArrayBuffer id is too long (65 bytes)", TypeError);
     new CreateCredentialsTest("options.publicKey.user.id", new Int16Array(33)).runTest("Bad user: Int16Array id is too long (66 bytes)", TypeError);
     new CreateCredentialsTest("options.publicKey.user.id", new Int32Array(17)).runTest("Bad user: Int32Array id is too long (68 bytes)", TypeError);
@@ -34,23 +33,9 @@ standardSetup(function() {
 
     // // user.name
     new CreateCredentialsTest({path: "options.publicKey.user.name", value: undefined}).runTest("user missing name", TypeError);
-    new CreateCredentialsTest("options.publicKey.user.name", {}).runTest("Bad user: name is object", TypeError);
-    new CreateCredentialsTest("options.publicKey.user.name", null).runTest("Bad user: name is null", TypeError);
-    new CreateCredentialsTest("options.publicKey.user.name", "").runTest("Bad user: name is empty String", TypeError);
-
-    // // user.icon
-    new CreateCredentialsTest("options.publicKey.user.icon", {}).runTest("Bad user: icon is object", TypeError);
-    new CreateCredentialsTest("options.publicKey.user.icon", null).runTest("Bad user: icon is null", TypeError);
-    new CreateCredentialsTest("options.publicKey.user.icon", "").runTest("Bad user: icon is empty String", TypeError);
-    new CreateCredentialsTest("options.publicKey.user.icon", "http://fidoalliance.co.nz/testimages/catimage.png")
-      .runTest("Bad user: icon is insecure", "SecurityError");
-    // // TODO: unicode tests for icon URL (see also: USVString)
 
     // // user.displayName
     new CreateCredentialsTest({path: "options.publicKey.user.displayName", value: undefined}).runTest("Bad user: displayName is undefined", TypeError);
-    new CreateCredentialsTest("options.publicKey.user.displayName", {}).runTest("Bad user: displayName is object", TypeError);
-    new CreateCredentialsTest("options.publicKey.user.displayName", null).runTest("Bad user: displayName is null", TypeError);
-    new CreateCredentialsTest("options.publicKey.user.displayName", "").runTest("Bad user: displayName is empty String", TypeError);
 });
 
 /* JSHINT */