184.108.40.206.6 Receiving an IMAP4_AUTHENTICATE_NTLM_Cancelled_Response Message
The expected state is sent_authentication_request or inside_authentication.
If the client receives an IMAP4_AUTHENTICATE_NTLM_Cancelled_Response message, the client MUST change its internal state to completed_authentication and consider the authentication to have failed. The client can then take any action it considers appropriate. These extensions do not mandate any specific course of action.