I have several surveys that were created using Survey123 Connect. They are intended for use by the public so sharing settings are set accordingly. Everything works smoothly if the user is on wifi, but if they load the survey using cellular data, the error "You do not have permission to submit this survey record. The feature service for this survey does not exist or is not accessible" shows at the top and they are unable to submit.
I can't emphasize enough that it all works on wifi - so I don't think there is a missing feature service nor is it a permissions issue.