Basic Troubleshooting
Please completely close and restart the game, and reboot your device. Most bugs are resolved by these two steps.

App Optimization
Update to the latest version from the store, and go to Settings → Apps → PUBG Mobile → Clear Cache.

Still having issues?
When contacting Customer Support, please provide details of the error, screenshots/videos, your device model name, and your OS version.

Tips
Checking your Wi-Fi connection, closing unnecessary apps, and ensuring sufficient storage space can also be helpful.