The password is not being accepted when accessing the Symantec Endpoint Protection (SEP) Client GUI. You are able to access the SEP GUI on other client machines that are in the same group and share the same policy serial number.
Error: "The password you entered is incorrect. Please try again."
The policy has been corrupted or changed and the password in that policy is corrupted.
The policy may be corrupted. You need to force the client(s) to retrieve a new policy by moving the client(s) to a temporary group and then moving it back to its original group. This process will force the client(s) to retrieve a new policy from the manager.