unix_chkpwd[xxx]: password check failed for user (xxx)

For user locked out after too many failed attempts, checking and modifying the permissions and SELinux context as needed did not resolve the issue. This successful solution was offered at Red Hat Customer Portal

However, I was able to resolve the issue by
1. Changing the user password,
2. Temporarily modifying the pam_faillock attribute for the same user using authconfig,
3. Testing they could log in remotely (ssh), and then
4. Removing the temporary pam_faillock attribute for that user.

auth [success=1 default=ignore] pam_succeed_if.so user in user1:user2:user3