"An error has occurred with the team invitation."

I've deployed several Acrobat DC licenses successfully by assigning them to users in my organization.  One user in particular is presented with the following after following the email invitation link and signing in to DC:

"Unknown Error: An error has occurred with the team invitation.  Please talk with your team administrator."

I've tried reclaiming his license and reassigning one, but he gets the same result.  I'm at a loss to troubleshoot this further, as there is no significant difference between the process for his installation and those that I've already completed successfully.