Symantec Endpoint Security (SES) client is upgraded automatically from previous version to 14.3 RU3 . But SES client user interface - [Help] - [Troubleshooting] - [Cloud Connection Status] shows "application error : 14" and client is not enrolled.
Windows Server 2016
Windows Server 2019
Symantec Endpoint Security 14.3 RU3
Symantec Endpoint Security 14.3 RU4
Issue is due to certificates present in the system that STIC believes are invalid when it tries to import it hence failing definitions initialization which makes the whole enroll fails.
The cause identified for this issue is fixed in 14.3 RU6 version of the SEP Client.