User Review( votes)
While trying to register our custom workflow activity from Isolation mode – Sandboxed to None for Dynamics 365 On Premise we got the below error
This was because the user through which we were trying to register the plugin in None Isolation Mode using Plugin Registration Tool was not having Deployment Administrator role.
Adding the user to that Deployment Administrator role through Deployment Manager fixed the issue.
Read more about it
Hope it helps..