Issue Clietns can't upgrade WHMCS properly on Plesk...

[RomanSan]

All of my clients with WHMCS installed on their domains are having issues when upgrading. To verify that this was not an issue with WHMCS I tried upgrading an instance running on pure Linux and it worked fine.

Would anyone know why the upgrade process for WHMCS would fail on Plesk? (WHMCS V8.2.0)

 

[JulianDot]

can you provide more details about those fails ?
there is a log file in /install folder, can you post its content ?