IFORM FOR IOS ERROR MESSAGES
To resolve this error please re-sync your device. This is a fail-safe built in that doesn't allow children (subform records) to be sent to the server without having a valid PARENT_RECORD_ID.
Typically the cause of this error is you have synced your device in an area of poor connectivity and the device needs to be synced to obtain a valid PARENT_RECORD_ID.
** Please update your iForm app to at least 8.20 where we fixed a bug where records were being orphaned due to missing PARENT_PAGE_ID. This will resolve the error message.