New tenant locked – AADSTS5000228 and HTTP 401, only global admin, need to check trial/subscription

I will answer you in English based on your post. As a friendly suggestion, posting in Korean may help your question reach more community members who are familiar with your preferred language.

Please note that this forum is a community support space. Community members and moderators cannot access tenant information, check subscriptions, cancel trials, restore tenant access, or receive tenant details through private messages. I can only provide guidance based on publicly documented processes and experience.

Dear @Simon Bumseok KIM,

I hope you’re having a good day. 

I'm sorry to hear you're experiencing this issue.

Because you cannot access either the Entra Admin Center or the Microsoft 365 Admin Center, this has effectively become a tenant access recovery scenario rather than a standard sign-in issue.

Unfortunately, the community cannot restore access or verify whether a subscription exists. The appropriate next step is to contact Microsoft Support so they can investigate the tenant status and, if necessary, verify ownership.  

Please try to find the related hotline number to call the frontline let them raise a ticket for you: Customer service phone numbers - Microsoft Support 

If you choose to contact Microsoft Business Support by phone, you may first be connected to an automated system before contacting a support professional. Based on similar cases of administrator lockouts, the conversation can go something like this:

Automated system: Are you calling as a private individual or a business customer?

You: Business customer.

Automated system: What do you need help with today?

You: Authentication problem.

Automated system: Which Microsoft product or service is affected?

You: Microsoft 365 for business.

Automated system: Can't sign in to the Microsoft 365 Admin Center?

You: Yes.

Automated system: Do you have another administrator in your organization?

You: No, I'm the only administrator.

Automated system: Are you a global administrator for the affected tenant?

You: Yes.

Automated system: Are you calling about an existing support case, or would you like to create a new one? You: I need to create a new support case.

In many cases, the automated system will then indicate that it can connect you with a support representative who can help create a support request and forward the case to the appropriate recovery team.

I would also recommend calling during opening hours when possible. From my experience, it can be difficult to reach the right support queue at times, and automated systems don't always behave as expected. If you can't get through on the first try, consider trying again later or at a different time of day.

If your organization’s Office 365 Business subscription was purchased through a partner or reseller, and you’re unable to open a service request directly, you may also contact the reseller’s support provider and ask them to open a support request on your behalf.

Alternatively, you can try set up a new trial tenant and submit your support request, please follow this link to create a trial tenant: Compare Office 365 Enterprise Pricing and Plans | Microsoft 365 - after that you will be able to access to Microsoft 365 Admin Center to raise the ticket

Assuming that you have already created an account after registering a free trial and you can go to Microsoft 365 admin center and click Support > Help & support icon to raise your ticket. The agent will be able to create a ticket for you under the affected tenant and then transfer this ticket to Data Protection team who could help you to regain access.

Please mention that you are raising ticket on behalf of the affected tenant that you do not have access to. The support team will help you to create ticket on the affected tenant then later on the Microsoft Data Protection team will assist you.

Note: This process will take more time than usual (7-14 working days) for your account to get access again as Data Protection is always overwhelmed with the number of tickets.

If you do create the trial and it resolves the issue, please remember to cancel the subscription afterward to avoid any related charges. This new trial tenant will not give you access to any of the data or settings in your original locked tenant. It is solely a temporary means to contact Microsoft support.   

Regarding the KRW 1,000 charge, that small amount is often used as a temporary card verification or authorization hold during registration. However, only Microsoft Support or the billing portal can confirm whether a paid subscription or trial was actually provisioned for the tenant.

I hope you're able to regain access quickly and verify the subscription status with Microsoft. Please feel free to share any updates, and I'll do my best to help guide you further.

Warm regards,  

If the answer is helpful, please select "Yes, accept answer". If you have any questions or new updates, please feel free to comment below.