What is alert 8151?


A user has attempted to logon to GMS using the POP3 protocol but failed. The account exists, but the password was wrong. The failure could be for several reasons:

  • The user did not provide the right details;
  • someone is attempting to gain illegal access; or
  • The authentication source was not available

In this case, session Undefined was processing a connection from a client at Undefined. The user claimed to be Undefined@Undefined and their client issued the command


GMS responded with

-ERR User unknown

. Note, the error given to the user is u201cUser unknownu201d so that should this be someone trying to break into your system, they will not know if the user name or password is incorrect.

To resolve this problem you will need to check that the authentication source is available and the user has entered their details correctly. Check the details of the error code for more information. You may also consider changing the user’s password if they have forgotten it.

See Also:


Keywords:failed logon POP3 user password 8151

Was this article helpful?

Related Articles


Need Support?

Can't find the answer you're looking for?
Contact Support