Environment
Secure Messaging Gateway (SMG) v7, March 2022 update

Situation
After applying the March update and restarting the appliance, no longer able to access the SMG Admin Console on the non-default port of 443.

The browser error shows:

Secure Connection Failed
An error occurred during a connection to smgserver.mydomain.com:20443. SSL received a record that exceeded the maximum permissible length.
Error code: SSL_ERROR_RX_RECORD_TOO_LONG

Attempting to view the certificate using: openssl s_client -showcerts -connect 127.0.0.1:20443 will fail with 'No client certificate CA names sent'.

Cause
As part of the March update, the /etc/apache2/conf.d/smg.conf file was replaced with a new, enhanced version. If the default port of 443 had been changed prior to applying the update, the new smg.conf file will revert back to using port 443.

Please find resolution on support portal here