Cannot put on other devices

I cannot synch this app on any of my kids devises. I have spent all day trying to figure it out. I put in a help request but no reply. Very frustrating. Ourly.help was so easy to upload and went smoothy on my kids devises with just an email invitation but their currency is only is U.S dollars for chores which doesnt work for us.

The Turret Core about iAllowance (Chores Allowances), v2.4.0