Try using a third party like app any cast and google home at first. If the issue still persist factory reset your tv. I also faced similar issue on my MI TV. Clearing data of miracast didn't help. So had to factory reset my TV.
Try using a third party like app any cast and google home at first. If the issue still persist factory reset your tv. I also faced similar issue on my MI TV. Clearing data of miracast didn't help. So had to factory reset my TV.