After upgrading Symantec Messaging Gateway (SMG) from 10.6.6 to 10.7.3, some mails are returned with the subject "casoop crashed on signal 11"
Further investigation shows the bmserver_log records and issue connecting to the CAS Host (see log extract below).
2020-09-23T00:00:07+03:00 (ERROR:13644.3880999168):  casoop: websocket connection to CAS server 192.168.1.5 threw exception: connection hdl was not set.
2020-09-23T00:00:43+03:00 (ERROR:15252.1885337344):  casoop: websocket connection error received by on_fail handler: server 192.168.1.5; Timer Expired
Release : 10.7.3
Component : SMG
The casoop service manages communication between the SMG (Symantec Mail Gateway) and Symantec CA (Content Analysis) servers. The error indicates that either the websocket connection could not be established or that the websocket connection between SMG and CAS was reset by some intermediate firewall.
Please ensure that SMG is configured with the correct IP address and API key for connection to the CAS server and that the required ports are open in any intermediate firewall.