This is to help participants (a.k.a. respondents, testers, users) using an iOS device, trying to join a session, but can't progress because she/he faces this rather unusual problem:
the participant is trying to join a session, goes through set-up/permissions
the participant reaches the final stage of set up/permissions before connecting with the researcher, and taps Start broadcast
the participant can't progress/faces the error message "Not available when AirPlay, CarPlay, Restrictions, or screen mirroring is active".
This error message is generated by iOS, so it has nothing to do with Lookback's app for iOS devices. But if no other app/function on the device is screen sharing, e.g. Airplay/CarPlay/screen mirroring, like the error message suggests, this problem could be caused by a restriction that's activated on the iOS device in question. If so, following these few steps should fix it:
Go to Settings ➡ Screen time ➡ Content & Privacy Restrictions
Tap Content & Privacy Restrictions
Set Content & Privacy Restrictions at the top to off, if it's toggled on
If you want to leave other settings in Content & Privacy Restrictions switched on, tap Content Restrictions.
Scroll down to the headline Game center and check that Screen Recording is set to Allow.