iPhone stops trusting computer after a few minutes

Greetings, snowwika.

I see that your iPhone is experiencing issues with "Trust This Computer". You regularly need to re-trust from your iPhone, and then it shortly forgets it again. I'm happy to help.

About the 'Trust This Computer' alert on your iPhone, iPad, or iPod touch

"Get help

If you tap Trust or Don't Trust but iOS doesn't accept your answer, or if the Trust alert won't appear, follow these steps. Try again after each:

1. Make sure that your computer has the latest version of iTunes. 
2. Disconnect and reconnect your iOS device from your computer.
3. Restart your iOS device and your computer.
4. Reset your Trust settings.

If the above steps don't help, go to Settings > General > Reset and tap Reset Network Settings. This also resets Wi-Fi networks and passwords, cellular settings, and VPN and APN settings that you’ve used before.

If you downloaded iTunes for Windows from the Microsoft Store, make sure that iTunes Mobile Device Helper is enabled as a startup item.

If you still need help, contact Apple Support."

Take care!

Thank you for trying those steps, snowwika. It's appreciated. Since the previous steps provided didn't resolve the issue, it's time to contact Apple Support.

Apple -Support - Solutions -- Apple Support will be able to troubleshoot this issue with you further.

Cheers.