Step 1: First try restarting your iPhone by holding the Side button and Volume Up or Down button simultaneously until the power off slider appears. Slide to turn off.
Step 2: Once the phone is off, hold the Side button again until you see the Apple logo to restart the iPhone.
Step 3: Check for any iOS software updates and install if available via Settings > General > Software Update.
Step 4: Reset network settings by going to Settings > General > Reset > Reset Network Settings.
Step 5: If issues persist, you can contact Apple Support via phone, chat, or booking an appointment at an Apple Store for troubleshooting assistance.