Kindly be informed that if your are using double sim mobile, kindly make sure that the sim you are using to call is the same in which internet is turned on. Otherwise you won't get data connection during the call.
If the issue still persist, kindly register your concern in Samsung Members app (Samsung Members app > Get help > Feedback > Error report/ask question). Note: Please send device log files within 15 minutes of issue occurrence along with the exact issue details.
