3.2.5.1.2.2 NTLM Returns Success, Indicating Authentication Completed Successfully

If the server passes an AUTHENTICATE_MESSAGE NTLM message with the correct user name and password to the NTLM subsystem, the NTLM subsystem returns success. The server MUST return the IMAP4_AUTHENTICATE_NTLM_Succeeded_Response message and change its internal state to completed_authentication.