Show the B2B-blocking proxy address in my tenant's logs
I try to invite email@example.com to my tenant (via Azure AD B2B), but get the error message "The user you're inviting already exists in the directory." But there are NO traces at all of that account in my tenant.
It turns out that the firstname.lastname@example.org have another proxy address (email@example.com) in THEIR OWN TENANT, and a user in my tenant also happen to have firstname.lastname@example.org as proxy address. There are valid reasons for this to occur.
I makes sense that you cannot have more than one proxy address per tenant, but there is no way for us to find out which proxy address that is blocking based on the only information we have available (email@example.com).
The colliding proxy address (not the one we try to invite) should be a part of the error message or at least be available in the logs. That way we could solve this ourselves.
Today we need to contact Microsoft Support to find it out.
Attached an image of the error message as it looks today.