I'm currently migrating from an on-premise setup to Office 365, and we initially used one of our admin email addresses to establish the new global admin account in Office 365. We've successfully moved about 80% of the mailboxes, and most are functioning well. However, the admin email used for the setup is now unable to log in. I can access Outlook Web App just fine, but the mobile apps (like Nine Email) don't work, and the desktop Outlook keeps prompting me for login credentials for a service but doesn't specify which one. Any advice on how to resolve this would be much appreciated!
2 Answers
When migrating, be mindful not to have an existing user email set as a global admin. It's better to create a new user for that role. Also, keep in mind that an email can belong to one user in a tenant and still be valid in another. Regarding desktop Outlook, if you're using the classic version (2016 or 2019), make sure you run all necessary updates beforehand to avoid login issues.
You might want to try removing the Outlook profile and see if that fixes the login issues. OWA should be your primary check for functionality since it reflects the true status of Office 365. Everything else is secondary to that.
I just attempted to create a new mail profile through the control panel, but I ran into a snag. It fails to find the account unless I select between Microsoft 365, POP/IMAP, or Exchange ActiveSync. No luck with setting up a new profile.
I think I might have discovered the root of the issue. It seems this email might also be linked to another Microsoft account. What’s the best way to go about resolving that? My other users get a direct password prompt, but this one asks if it's a Work/School or Personal email first.
We actually found that out early on and set up a different global admin with an onmicrosoft.com address. But the original admin's email was already tied to the account setup. Can you elaborate on what kind of updates Outlook needs? We're currently on Outlook 2019.