Error message in Photoshop Elements "...not the right kind of document."

I'm not aware of any Photoshop CC plug-in that can't be used in Elements.  The error message does not seem to be a plug-in related message.  So, we definitely need more details about the plug-in and what action you were taking to generate the error message.

Are you sure it's not a Photoshop plugin rather than a Photoshop Elements plugin?

Which plugin are you trying to install?

Is it compatible with PS Elements 2021?

Let me move this to the Photoshop Elements forum for you, which is the appropriate forum for your question.

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