Liveupdate distribution failed - observed once in a month at random time.
2021-02-01 09:07:46,523 [transfer27] ERROR rcl.HttpHelper  - Error while uploading file : C:\TempDownload\minitri.flg
2021-02-01 09:07:51,524 [transfer27] ERROR connection.ConnectionManager  - Connection failed for server Default Production Distribution Center serverID - 4
This seems to be a residual JVM property issue. When the proxy config is being applied while creating connection for downloading content or for telemetry data submission, the JVM wide property http.proxyHost and https.proxyHost gets set and never removed which causes the JVM to use the same proxy configuration for future connection attempts and subsequently fails.
Symantec is aware of the issue and will be fix in Liveupdate Administrator 2.3.9 version.