I tried creating a global user to use it with an external service. The external service wasn't able to access it due to administrator rights were not applied to the user despite checking all the privileges after creating an account.
Error: The test connection to the database server has failed because the supplied account does not possess administrative privileges:
Access denied for user 'percona'@'%' to database 'd597b03c0af1a8'
While using CLI, I manually granted all privileges and it worked perfectly.