Scout not matched on official roster?

I keep getting the following message when trying to update advancement for a scout:
(Scout name) has not been matched with a Scout in your Units official roster. Please check with your council.

However, the scout has been on our roster/charter for years. His BSA number is not even showing up on the scout’s main page. I am the Scoutmaster (also not new) so I have been able to add, change, etc information for a while.

What is the Scout’s member ID number (from my.Scouting)?

No names, please.