Thanks for responding, I've tried those two different scopes and even account scope set as Global but without success. It still show the same error message and in console it says,
_services/entity-grid-data.json/f46b70cc-580b-4f1a-87c3-41deb48eb90d 500 (Internal Server Error)
I checked with odata and fetchXml and the result is empty/null with no errors, its just blank. So its hard to find what's the problem.
I have tried to just display the contacts of the Account and that works just fine so nothing wrong there, i just want to display the account details (account form) of the contacts (parentcustomerid) related to it.