for some techs: Could not create transport for E-Mail messages: 421 4.3.2 Service not active


Since yesterday one of our techs ( as customer oder tech - role ) sometimes get following error-message, when he tries to send a notification-Mail by clicking the send-Button ( create new ticket ).

Also he get sometimes no notification-Mail when e ticket escalates to him ( same error-message ).

For the other 40 techs it works fine.