diff --git a/security/manager/ssl/src/SSLServerCertVerification.cpp b/security/manager/ssl/src/SSLServerCertVerification.cpp
index 44fda31c1581..56ac90f997a3 100644
--- a/security/manager/ssl/src/SSLServerCertVerification.cpp
+++ b/security/manager/ssl/src/SSLServerCertVerification.cpp
@@ -321,7 +321,7 @@ CertErrorRunnable::CheckCertOverrides()
       if (NS_SUCCEEDED(nsrv) && haveOverride) 
       {
        // remove the errors that are already overriden
-        remaining_display_errors &= !overrideBits;
+        remaining_display_errors &= ~overrideBits;
       }
     }