screen mirroring losing video, audio ok

I'm screen mirroring from my iPhone 8 plus, 13.4.1 to my Apple TV 4K 13.4.6. hard wire CAT5 internet.

Phone connects as a remote for the Apple TV ok.

Sometimes mirroring works great, but other times it will only have audio or sometimes no audio or video. I tried to trouble shoot it tonight by upgrading firmware on the Apple TV, then rebooting the phone and it finnaly all worked again. Why would I have t keep rebooting my phone to make it work?

beginning to be a little frustrating.

Thank you in advance.

Any help would be appreciated.

Harvey