Hey there KNFF12,
Let's team up to get both phones working correctly while accessing cellular data.
While you may need to reach out to your carrier about this, we only recommend that as a last step.
As you mentioned still receiving a 4G signal, along with it having no issues after restarting, let's continue from there by confirming some basics:
- We see in your post that you have iOS 14 installed, but the latest version is 14.4.1. You can verify the version number installed within Settings > General > About. Here's a link that'll show how to first back up, then Update your iPhone, iPad, or iPod touch.
- Afterwards, this link shows how to Update your carrier settings on your iPhone or iPad.
- If you check in Settings > Cellular > Cellular Data Options, you'll want to make sure Low Data Mode is disabled.
- If you have any VPN software installed on your iPhone, you'll want to remove it, then test for the same issue. A VPN is usually found in a work office environment, and may have rules set that could cause the issue you're experiencing.
- If the same issue remains, the next step would be to reset your network settings. This can be found under Settings > General > Reset > Reset Network Settings. As this erases your saved Wi-Fi network/password, cellular settings, and VPN/APN settings, you'll want to make sure those settings are saved elsewhere in case you need them after troubleshooting.
Take care!
