Can't add new administrator to AZT portal

I see the same behaviour and I'm a "owner" in the AZT portal. If my memory serves me correct, last time I was involved with adding users it was the reseller who invited the customer in to AZT that had to add new Administrators to the portal. 

The account you try to add must be a valid Google account. If there's no google account associated with the email address, this shows. 

I can replicate this reliably, when adding a known @gmail.com account or a Google-enabled domain account it works. When I try to add a known non-Google account through a private domain I haven't created a Google account for, this error shows.

Edit to say: I wrote that a little too-definite; the error is a generic 500 app error so other reasons could generate it, but this is most common 🙂 

Thanks, I'll try both options

Yep, we have seen similar before.

The account you want to add needs to have a Google account created with (doesn't need to be a gmail account).