Unsynced Records not sending

Unsynced Records not sending

Hi
The main reason we are trying out Zoho Forms is so we can get users to fill out the forms on a tablet on site and they will sync when they get back to a branch with wifi.
I'm sure I tried this with a different form and it work, ie. when Wifi became available the forms sent without any extra user action.
But the submitted forms are not syncing, I can see them under ''Unsynced Records' on the tablet, when I open them they are missing selections that were definitely made.
If I submit them again from here, with wifi, they go through fine.
Please help.

Thanks
Richard