Photoshop CC2021 issues
One of our users reports issues with ProSelect being unable to reliably connect to Photoshop after updating to Photoshop version 22.2 (the latest release of CC 2021) on a Windows 10 machine.
The symptoms were that ProSelect would work when using the "Test Photoshop Connection" check in ProSelect (after restarting both software) but Photoshop would no longer respond to external commands after running Custom Effects actions. They reported that this version of Photoshop was also not working normally when used by itself.
The solution was to uninstall the latest version and revert Photoshop back to version 22.0.1.
Hopefully, Adobe will sort out these issues in the next update. We do not know if these issues are present in the Mac version.
KnowledgeBase Article: Photoshop CC2021 issues