Following the update to Messaging Gateway (SMG) 10.7.3, attempting to connect to the Control Center web application fails with an SSL error immediately or fails after being prompted by the browser to select a certificate.
Messaging Gateway 10.7.3 now requests a client certificate as part of the TLS security negotiation. If any client certificate is presented before SMG is configured to trust it or the Certificate Authority that signed it, SMG will refuse the connection with a SSL error.
Patch 281 has been released to address this issue. Updating SMG 10.7.3-5 with patch 281 should resolve this issue.
The patch can be downloaded and installed from the update servers using the instructions in Installing and removing patches for Messaging Gateway
Release information can be found in Symantec Messaging Gateway 10.7 Release Notes and Late Breaking News
This issue can also be resolved by uploading either the client certificate or the certificate authority public certificate that was used to sign it to the control center as follows: