Microsoft Outlook

Question

I use the Google Chrome browser to access Microsoft Outlook. However, since this morning, Microsoft Outlook has not been opening on either the computer or the laptop. Even when using the Microsoft Edge browser, Microsoft Outlook fails to open. On my mobile, only messages from yesterday or earlier are visible—specifically, emails received yesterday and those sent up until yesterday. I am unable to receive or send emails on the mobile today. This issue is affecting all laptops and computers in the organization. We hold the Microsoft Outlook admin account.

[Moderator note: personal info removed]

Answer 1

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Hello @Sandy IT

I would like to first clarify that this is a user-to-user support forum, and we are not Microsoft support. Moderators here do not have backend access and cannot directly intervene in Microsoft products or perform escalations. We can only provide technical guidance and best-practice recommendations based on reported issues.

The specific error Microsoft.Exchange.Data.Storage.TenantAccessBlockedException usually indicates that the Microsoft 365 tenant has been placed into a restricted or suspended state.

In most cases, this happens due to:

• An expired or unpaid subscription
• A failed or expired payment method (for example, credit card issues)
• Less commonly, a security‑related restriction or policy action

If you are a regular user (employee or student), there isn’t anything you can fix on your side. You’ll need to contact your IT administrator for assistance to check if you have appropriate license.

If you are an administrator, you can check the following:

• Billing and subscription status: Go to Microsoft 365 Admin Center > Billing > Your products and confirm the subscription is Active.
• Payment method: Go to Billing > Payment methods and make sure the payment method is valid and hasn’t expired or been declined. If the subscription has expired, Microsoft may place the tenant into a Disabled state, which blocks user sign-in and email access. After resolving the billing issue, access is typically restored within a few hours, although in some cases it may take longer to fully propagate.
• Check for security or policy restrictions: In the admin center, review Health > Message center for any alerts related to tenant restrictions (for example, “restricted customer” or similar notices).

If everything looks correct but the issue persists, it’s likely that the tenant is still restricted on the backend, and you may need to contact Microsoft Support to have it reviewed and lifted: https://learn.microsoft.com/en-us/microsoft-365/admin/get-help-support?view=o365-worldwide

I hope this information is helpful. Keep us informed about the outcome.

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Answer 2

The error message in the screenshot (TenantAccessBlockedException, HTTP 500, affecting all users and all devices) indicates a tenant‑level backend problem in Exchange Online, not a browser or client issue. Local troubleshooting (changing browsers, clearing cache, restarting devices, etc.) will not resolve it.

As tenant administrators, the next steps are:

1. Check Microsoft 365 service health
   • Sign in to the Microsoft 365 admin center and open Service health.
   • Under Exchange Online, verify whether there is an active incident or advisory that matches the time your Outlook access stopped working.
   • If there is an incident, follow the guidance and updates provided there.
2. Run Microsoft 365 diagnostics (admin)
   • From the admin center, run the Outlook User Connectivity diagnostic for one of the affected users.
   • The diagnostic will run automated checks against the mailbox and connectivity and may surface known issues or remediation steps.
3. If no incident is shown and diagnostics do not resolve it
   • Open a support ticket from the Microsoft 365 admin center and include:
     • The full error text including TenantAccessBlockedException and the UTC time from the error page.
     • Confirmation that the issue affects all users and all clients (web, Outlook, mobile).
   • This allows Microsoft support to check for tenant‑level blocks, account/tenant configuration issues, or backend faults and apply a fix on their side.

Because the problem is tenant‑wide and appears simultaneously on web, desktop, and mobile, it aligns with the backend/account issues described in the references, which required investigation and correction by Microsoft support rather than client changes.

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References:

• Fix Outlook connection problems for Microsoft 365 account
• Issues sending and receiving email
• Not able to have access to my email ! - Microsoft Q&A
• Outlook.com address returning TooManyObjectsOpenedError - Microsoft Q&A
• Unable to send encrypted emails in Outlook for Mac and Outlook.live.com (admin account) since 03/13 - Microsoft Q&A