If we have this problems, then try to replace camera glass lens with original one at Xiaomi authorized service center. Some software / firmware version also will make XIAOMI REDMI NOTE 7 camera auto focus can not work properly. Please try to backup with latest firmware or Android version upgrade.
Try restarting your phone. Check the camera permissions. There are two ways to give the permissions back to this particular app, here is the easier one. If the above methods do not solve your problem, he is one more solution you can try which has been shared by a Xioami user.

If the camera does work then it the Camera app that's glitching out and you just have to clear the cache and the data of the camera app. Tell me if this fixes your issue and makes your camera work without displaying error messages.

1. Check XIAOMI REDMI NOTE 7 camera permissions 2. Check if another app is already using the XIAOMI REDMI NOTE 7 Camera 3. Force Stop XIAOMI REDMI NOTE 7 Camera 4. Cool down the XIAOMI REDMI NOTE 7 5. Clear the XIAOMI REDMI NOTE 7 Camera Cache 6. Restart the XIAOMI REDMI NOTE 7 7. Update Android on XIAOMI REDMI NOTE 7 8. Redmi Note 7 Front Camera not working, Repair #PGT . Contact for Mobile Repair Course from Basic to Advance Level. It's cable reimagined No DVR space limits. No long-term contract. No . 268 352 477 8 402 204 6 251

redmi note 7 camera not working