iPhone 5 or earlier facetime doesn't work

[Globug]

Just a quickie here, but my grandma's iphone 5c has recently stoped letting facetime work. We can hear each other, and i can see her, but she's getting the can't see you due to whatever thing that pops up on the screen.

Is this an issue with the phone or software? any ideas on how to fix it?

 

[akash.nu]

We need the exact message.

 

[Globug]

As far as I'm aware there's only 1 message that prevents you from seeing someone else on facetime but allowing you to hear them

 

[Hal~9000]

Maybe Apple let the FaceTime certificate expire (“oops!”) on older devices again? https://9to5mac.com/2017/02/02/apple-facetime-lawsuit-ios-6-ios-7/