JohnW I’m afraid there is not much I can help with if I this is all you can share. Obviously, this functionality was tested many times and was working fine. There should be something specific to your case than makes application function not as expected, that is why I am looking for details that are specific to you, not the common description of the function.
Probably it might help if you record a video using your phone showing every step of the process? You can share in on google and send a link to support@tonfotos.com