@shakeel8951
I understand you're experiencing an issue with your iPhone restarting randomly. I've reviewed the summary of your issue, and it seems like you've already tried restarting your iPhone 12 Pro Max which is running iOS 15, but the problem persists.
Based on the information provided, here are a few steps you can try to resolve the issue:
1. **Update iOS**: Ensure your iPhone's software is up to date, as this can often resolve issues with stability and performance.
2. **Check for App Updates**: Sometimes, an app can cause system instability. Make sure all your apps are updated to their latest versions.
3. **Free Up Space**: If your iPhone is low on storage, it can lead to performance issues. Try deleting unnecessary files or apps to free up space.
4. **Reset Settings**: You can try resetting all settings on your iPhone. This won't delete your data but will reset system settings to their defaults.
5. **Backup and Restore**: If the issue continues, back up your iPhone and perform a factory reset. This will erase all data, so ensure you have a backup.
If none of these steps work, it may be a hardware issue, and I would recommend contacting Apple Support or visiting an Apple Store for further assistance.
If you've already tried all the above steps, please let me know so I can assist you further. If your issue is resolved, I can go ahead and close the support ticket for you.