MFA error 500121 – locked out of existing Microsoft Entra tenant – need Tenant Recovery

Question

MFA error 500121 – locked out of existing Microsoft Entra tenant – need Tenant Recovery

hejdschdee0doubleZ 0

I am locked out of an existing Microsoft Entra work/school account because the registered MFA methods are no longer usable.

Password reset through SSPR using the registered alternative email address was successful. The new password is accepted. Sign-in then stops at MFA.

Microsoft Authenticator verification codes are rejected with error 500121. Authenticator push notifications do not arrive, and no alternative MFA method is offered at sign-in.

I have already exhausted the normal recovery and support routes:

SSPR password reset completed successfully.
MFA re-registration cannot be reached because sign-in requires the inaccessible MFA method first.
Microsoft telephone support did not provide a working recovery route.
I created a separate Microsoft 365 Business trial tenant solely to obtain access to Microsoft Support.
The Microsoft 365 Admin Center in that temporary tenant does not provide a usable way to create the required support case.
I then accessed Azure Help + Support from the temporary tenant.
Azure correctly classified the problem as Microsoft Entra Sign-in and Multifactor Authentication, but the Contact Support path only offers Azure Support Plans and does not allow me to submit the recovery case.

IMPORTANT: The Microsoft 365/Azure tenant I am currently using is only a temporary support tenant. It is NOT the affected tenant.

The affected account belongs to a different, existing Microsoft Entra tenant.

I need assistance from a Microsoft moderator to get a case opened/escalated to Data Protection / Tenant Recovery so that ownership can be verified and MFA access for the affected account can be restored.

I can provide the affected account address, tenant/domain information, contact information and any required ownership verification privately to Microsoft staff. I am intentionally not posting those details publicly.

There is no other administrator available to reset the affected MFA registration.

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Demi Nguyen 2,005 Independent Advisor

Please note: This is a user-to-user Community forum. No one here can access Microsoft’s backend systems, create a support ticket, or make changes to your account, tenant, or billing information. You must contact Microsoft Support directly, as only an authorized support agent can assist with these requests.

Hello hejdschdee0doubleZ,

Thank you for providing the detailed information about the steps you have already taken.

In the Microsoft 365 admin center of the trial tenant, please go to Support > Help & support and check whether you can see the "Support Assistant" toggle at the top of the Help panel.

If the toggle is available, please make sure that Support Assistant (AI) is turned Off. Several customers have reported that the Contact Support option may not appear while Support Assistant is enabled.

Once Support Assistant is turned off, please enter a brief description of the issue in the Help panel and select "Get Help". The Contact Support option should then appear, allowing you to submit a support request directly to Microsoft Support.

User's image

If you do not see the Support Assistant toggle, or if Contact Support still does not appear after turning it off, could you please provide:

The exact name of the trial subscription you created.
A full screenshot of the Help & support panel, including all available tabs and options.

Please make sure that passwords, verification codes, and other sensitive account information are not visible in the screenshot. This information will help me better understand why the trial tenant is not providing the option to create a support request.

Kind regards,

hejdschdee0doubleZ 0 Reputation points

2026-09-15T16:36:56.1966667+00:00

Hi,

Thank you for your reply.

Subscription: Microsoft 365 Business Basic.

As requested, I have attached the requested screenshots of the Help & Support panel.

The Support Assistant is already turned off. However, the Contact Support option never appears. The only option available is the phone support information shown in the screenshots. I have reached to call these numbers to avail - either the number is not available anymore (alternative phone number: 069-....) or cannot be reached even during business hours (0800... - "sorry we are currently unavailable")

Could you please advise how I can create a support request if the Contact Support option is unavailable?
Demi Nguyen 2,005 Reputation points Independent Advisor

2026-09-15T17:25:39.9133333+00:00
Hi hejdschdee0doubleZ,

Thank you for the update.

Based on the information I found, the availability of the Contact Support option in the Microsoft 365 admin center may vary depending on the subscription and region. This may explain why the option is not available in the Help panel of your trial tenant.

Please try contacting Microsoft Support again using the phone number listed for your country or region on the following page: Contact Microsoft customer support | Microsoft Support

When you call the support number, you may hear an introduction of about 30 seconds such as "you can visit the link...". You can ignore this introduction and wait until you are presented with the options. Then press "1" as a business email user, and again "1" for technical help

In some regions you may initially interact with an automated system, so here is an example of how you can answer the prompts to reach the right team more quickly:

What kind of problem are you experiencing?

Answer: Authenticator

What products do you use?

Answer: Office 365 for business

Is this for an education or company account?

Answer: For companies

Are you an administrator?

Answer: Yes

Are there any other administrators in your organization?

Answer: No. I am the only admin in my tenant

Do you need a... Service request?

Answer: Yes. I need to create a ticket. Please send me direct to the Data Protection Teams.

I also recommend calling during normal business hours. In my experience, reaching the appropriate support queue may take more than one attempt, especially when the initial interaction is automated. If the first call is unsuccessful, please try again later or at a different time.

As another possible workaround, if you know someone who administers another active Microsoft 365 business tenant, you can ask that administrator to open a support request on your behalf.

I hope one of these options helps you reach the appropriate support team.
hejdschdee0doubleZ 0 Reputation points

2026-09-18T09:18:49.2066667+00:00

Hi @Demi Nguyen ,

Thank you. Unfortunately, I have already exhausted both options you suggested.

I have repeatedly tried the telephone support route, including being transferred and subsequently disconnected without resolving the issue.

I also already created a separate Microsoft 365 Business trial tenant specifically to contact Microsoft Support on behalf of the affected tenant. I can access its Admin Center as administrator, but it does not provide me with a usable way to create the required support request. I also tried Azure Help + Support. The issue was correctly classified as Microsoft Entra Sign-in and Multifactor Authentication, but the Contact Support route only offered Azure Support Plans.

Could you please escalate this to a Microsoft moderator who can initiate a Data Protection / Tenant Recovery case, or provide a private-message channel where I can provide the affected tenant and account details?

The affected tenant is NOT the temporary trial tenant.

I am ready to provide the affected account, tenant/domain information and any required ownership verification privately. I do not want to post this information publicly.

Thank you.
Demi Nguyen 2,005 Reputation points Independent Advisor

2026-09-19T17:10:46.81+00:00

Thank you for the detailed update.

I am sorry, but this is a user-to-user community, and I am only another community user. I do not have access to Microsoft’s internal support systems, so I am unable to transfer your request to a Microsoft moderator, create a Data Protection case, or provide a private communication channel.

Please do not post the affected tenant, domain, account details, or ownership information publicly. This information should only be provided privately to an authorized Microsoft Support agent during the verification process.

If you do not mind trying one additional workaround, you could consider creating an Enterprise trial tenant, such as an eligible Microsoft 365 E3 trial, and then check whether the Contact Support option is available in that tenant’s Microsoft 365 admin center: Microsoft 365 Enterprise: Compare Plans and Pricing

Microsoft currently advertises an enterprise trial option, but please note that availability and access to online support may vary by country, region, subscription, and how the subscription was obtained. Therefore, I cannot guarantee that this method will provide the support option that was missing from the Business trial tenant.

If you decide to try this option, please carefully review the trial terms and billing information before registering. Some trials require a payment method and may automatically convert to a paid subscription after the trial period. Remember to cancel the trial or turn off recurring billing afterward if it is no longer needed.

I am sorry that I cannot directly connect you with the appropriate team from this community.

Kind regards,