Endlessly popping up "Parallels Tools needs Update"

Every time I start Windows 11 VM, Parallels Tools Installationagent is asking to update Parallels Tools. But if I press restart, then after restarting Windows, same dialog appears:


I tried to uninstall Parallel Tools in Windows, but the I get this error ("The installer has encountered an unexpected error installing this package. This may indicate a problem with this package. The error code is 2503.)

Same error appears, if I try to uninstall Parallels Tools.
Any help much appreciated. Can't file a support request because I neither have an X-Account nor a facebook account. Annoying decision from Parallels support to not providing a simple e-mail for paying clients thogh.