onmicrosoft.com domain admin lost

Question

This has me stumped.

I have an Exchange 2019 server on premises. I believe during setup somewhere it made me create an onmicrosoft.com domain - and later I deleted that, after getting lost in the setup and doing SEVERAL times over. The server works well but I want to tie in Exchange Online Protection so I can use a relay and send from MS servers for email so I won't get flagged as spam or blocked. The initial setup was years ago, so I forgot the admin user on the onmicrosoft.com domain. When I bought EOP I just created a new onmicrosoft.com domain and tried to add my company domain in the setup but it fails stating that my company domain is tied to another account. It shows me the other onmicrosoft.com domain and what user I should login with (this is my work exchange email). I have no idea what that password is. If I try to reset it - it says I can't and only an admin can reset it. I get the email via my work exchange email stating that a user (me) has requested to reset the password and tells me to login to the admin portal to do so. So the paradox is if my own email is the admin, but I don't know the password and the password can only be reset in the admin portal - how do you fix this. I tried using the support button on the password reset page, but that only leads to an error about the page not working. I just want to remove my work domain from that old onmicrosoft.com account so I can register it on the new one that I bought the EOP for.

Thanks for any help!

Mike

Answer 1

Hello Mike,

I am glad to help you here. After looking through your whole post for several times, it main problem you got is you know the full admin email account, but don't know the password to login Microsoft 365 admin portal to un-tie the company domain from that tenant, please clarify if I misunderstand your scenario, thanks.

If so, first it is recommended contact another global admin of the "admin account" tenant to help reset the password, however my undertstanding is it maybe the only admin or you don't know the other admins in this round. For this case I'd like to share with you as the admin password is related to Microsoft customers' high level privacy, currently we don't have enough rights/resource on the admin account issue in the forum. And it could be only supported by the Microsoft 365 backend data protection team. So to get further assistance and help you quickly, it is recommended please directly contact Microsoft 365 Business Global Support based on your country or region and contact the back team to report your issue there, thanks.

Your understanding and patience will be highly appreciated.

Best Regards,

Oliver