Are both phones from or on the same network? Did you get either on a network provider contract? I'm assuming you have a new sim card as the P30 Pro is a 4G phone. You can try contacting your network provider to see if they can push network settings to your phone. Sometimes this can help. If you used SmartSwitch to setup your new phone. You can try clearing the Partition Cache on the phone. This will remove old, temporary and corrupted files from the phone, that can adversely affect it.