Can you pls attach the error log that says ' connector '.
So that i can understand your issue.
Most likely the user role has no Access Rule in the Domain Model for that Entity.
Go Make IT
(If this helped you please accept the answer)
Is there really nothing in the Mendix studio pro logs? A bit of a guess: could it be you are doing something that takes more than 5 minutes? In that case, set "call type" to "asynchronous" in the microflow settings.
If this is not the solution, does the browser log show anything? (Accessible via the browsers developer tools)