At the bottom of the page, each VoIP account currently provisioned on your system is listed and registration status appears on the far right. Possible status messages are:
Connecting - trixbox Pro is attempting to contact your VoIP Provider and register using the account information you entered
Rejected - the credentials you entered for the VoIP account were rejected by the VoIP Provider. The credentials were either entered wrong, or the VoIP Provider has not yet activated your account within their system