iPhone 11 Pro Max Smart Battery Case problem

Hello. After installing ios 15 on my iphone 11 pro max, my smart battery case stopped working correctly. When the phone is locked, a message appears that you need to unlock the phone to use the connected device. The phone at this moment does not receive charging from the case. If the phone is unlocked, it vibrates every minute and shows that charging is connected, as if it is connected to charging again and again. Please tell me how to fix it? Thank you