Cannot access Microsoft 365 Admin Center – "Selected user account does not exist in tenant 'Microsoft Services'"

Question

Cannot access Microsoft 365 Admin Center – "Selected user account does not exist in tenant 'Microsoft Services'"

Hana Gawlasova 0

Hi, I started a Microsoft 365 Business Premium trial using my custom domain email. My Microsoft Entra tenant exists, but I cannot access Microsoft 365 Admin Center.

Authentication is being redirected to the Microsoft Services tenant instead of my own tenant.

I receive the error:

Selected user account does not exist in tenant 'Microsoft Services' and cannot access the application ... The account needs to be added as an external user in the tenant first.

As I cannot access the admin account, I am also unable to ask for Support to verify that my Microsoft 365 Business tenant is correctly provisioned and that my administrator account is associated with the correct tenant.

I would be grateful for a workaround. Thank you.

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1 answer

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Answer 1

Hendrix-C 19,865 Microsoft External Staff Moderator

Hi Hana,

Based on your sharing, if you're routed to the tenant "Microsoft Services", the issue is likely that your custom domain account is considered as a personal account and when a personal Microsoft account is used to sign in, you can be routed to Microsoft Services tenant by default, where your business tenant directory is not available.

I suggest you first try signing in with your original onmicrosoft.com admin account to see if you're able to access Microsoft 365 Admin Center. When a trial created a tenant, it also created an initial tenant domain yourtenant.onmicrosoft.com with an original admin ******@yourtenant.onmicrosoft.com.

This matters because the custom domain may not yet be fully verified or associated with the tenant, but the onmicrosoft.com domain should belong directly to the tenant.

Please give it a try and let me know whether it works. If not, please feel free to reach out again in the comments on this post. I'm happy to assist you further

Thank you for your understanding and cooperation. I'm looking forward to your reply.

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Hana Gawlasova 0 Reputation points

2026-07-20T06:32:45.91+00:00
Hi Hendrix-C

Thank you very much for your suggestion.

I also believe that signing in with the original *.onmicrosoft.com administrator account would likely solve the problem. However, I have not been able to identify that account.

Here is what I have already checked:

I searched all emails I received during the Business Premium trial signup but could not find any message containing an *.onmicrosoft.com username or tenant name.

I have never knowingly signed in with an *.onmicrosoft.com account.

My custom domain has not yet been connected to Microsoft 365. My email is still hosted by another provider.

When I try to sign in with my custom domain email, I am consistently redirected to a personal Microsoft account (live.com) and eventually receive either AADSTS16000 or "Selected user account does not exist in tenant 'Microsoft Services'".

I can briefly access the Entra portal and see that a tenant exists, but as soon as I try to navigate or perform any action, an authentication prompt appears. After signing in again, I receive the tenant authentication error and cannot proceed.

Given that I cannot identify the original *.onmicrosoft.com administrator account, is there any way to discover the tenant's initial onmicrosoft.com domain or the original Global Administrator account from the information available during sign-in, or is this something that Microsoft Support needs to verify on the backend?

Thank you for your help. It is much appreciated.
Hana Gawlasova 0 Reputation points

2026-07-20T06:41:19.64+00:00
Hi Hendrix-C

Thank you very much for your suggestion.

I also believe that signing in with the original *.onmicrosoft.com administrator account would likely solve the problem. However, I have not been able to identify that account.

Here is what I have already checked:

I searched all emails I received during the Business Premium trial signup but could not find any message containing an *.onmicrosoft.com username or tenant name.

I have never knowingly signed in with an *.onmicrosoft.com account.

My custom domain has not yet been connected to Microsoft 365. My email is still hosted by another provider.

When I try to sign in with my custom domain email, I am consistently redirected to a personal Microsoft account (live.com) and eventually receive either AADSTS16000 or "Selected user account does not exist in tenant 'Microsoft Services'".

I can briefly access the Entra portal and see that a tenant exists, but as soon as I try to navigate or perform any action, an authentication prompt appears. After signing in again, I receive the tenant authentication error and cannot proceed.

Given that I cannot identify the original *.onmicrosoft.com administrator account, is there any way to discover the tenant's initial onmicrosoft.com domain or the original Global Administrator account from the information available during sign-in, or is this something that Microsoft Support needs to verify on the backend?

Thank you for your help. It is much appreciated.
Hendrix-C 19,865 Reputation points Microsoft External Staff Moderator

2026-07-20T22:42:39.8+00:00

Hi Hana,

If that's the case, I suggest first checking your mailbox for a confirmation email. When you first purchased your subscription, Microsoft sent a confirmation email to the address you used to register your Microsoft account. This email included your admin account details, which typically follow the format ******@yourcompany.onmicrosoft.com.

You can try searching your inbox for keywords like “Microsoft” or “onmicrosoft.com” to locate the confirmation email that has your admin credentials. You can also check your Deleted items folder just in case you accidentally deleted that email.

Please note that the email address used for purchasing and receiving notifications is not the same as the admin account required to sign in to the Microsoft 365 Admin Center for your business subscription.

If there is any update regarding the issue, please feel free to reach out again. I'm happy to assist you further.

Thank you for your cooperation and understanding.

Kind regards.
Hendrix-C 19,865 Reputation points Microsoft External Staff Moderator

2026-07-21T22:32:09.0466667+00:00

Good day Hana,

Hope things are running smoothly on your end.

Following up on the support thread we've been working on. If you need assistance with anything else, kindly respond to this post, and I will be happy to help.

I want to make sure everything is working as expected and that your experience remains uninterrupted.

Thank you for your patience and understanding throughout the troubleshooting process.

I look forward to hearing from you soon.
Hana Gawlasova 0 Reputation points

2026-07-21T22:46:00.2933333+00:00

Hi Hendrix-C, thanks very much for both your messages. I have thoroughly searched my inboxes for any onmicrosoft.com messages and I cannot locate them. Currently I am unable to make any changes to my Microsoft 365 Business Premium service (I need to add my custom domain and two users), as I am unable to access my admin account. My attempts to get in touch with Microsoft Support have failed. For Work Account support I need admin account access - which I am clearly unable to obtain. I tried the hotline to no avail.

I am seriously thinking about cancelling the subscription and establishing a new one - and this time being more careful about setting up my organization correctly. I run a small business and I need to get things going.

I am longing for times long past when it was possible to speak to someone you know, human, to call a hotline, give your order/licence number and someone would be able to help you in real time...

All the best

Hana
Hendrix-C 19,865 Reputation points Microsoft External Staff Moderator

2026-07-21T23:16:31.03+00:00

Hi Hana,

I have initiated a private message to ask some questions for more details so I could assist you further. Please take a look at your private message session.

Thank you for your cooperation and understanding. I look forward to your response.