Find my iphone won't work but I am signed in on the phone

fter 90 minutes with a second level support guy the fix turned out to be pretty simple and involved three steps:

Sign out of your account (Settings, click on your name, scroll to the bottom and sign out).

Do a "Force Restart" Hit the up volume key then the down volume key then press and hold the power button until you first see the Apple logo then an image that tells you to plug in your phone to restore. Then release the button. (It might be 30-seconds or more).

Press and hold the power button to power down then repress to power back up.

I hope this helps someone before they spend several hours trying to fix it.

Yes, location services is on all the way down to System Services. Why should the network make any difference? Shouldn't it work via cell network? Yes, it's worked in the past and all other devices show normally on iCloud.com Find my iphone.

i turned off and on location services for Find my iphone.

And, still when I open the app it asks me to sign in but I am already signed in! (Obviously because I routinely get 2-factor authentication notices).

Like I said, I've got several hours invested in troubleshooting this issue so please do send me to a generic page because I've most likely already read it and tried what it recommends.