Occasionally ParentPay will return an error message saying that there is a missing reg group from your pupil upload.
This article will teach you...
How to fix the error message for a missing reg group when it is stopping your pupil upload
How to resolve the issue
If when processing an upload you find that the year is missing from a reg group, then please check the setting below. People > Uploads > Upload Settings
Try toggling this option on/off and reattempting the upload in the first instance.
If the problem persists please contact ParentPay support.