Unknown error

Question

Why am I getting this error when opening Outlook? 

UTC Date: Information deleted for privacy protection
Client Id: Information deleted for privacy protection
Session Id: Information deleted for privacy protection
Client Version: Information deleted for privacy protection
BootResult: configuration
Back Filled Errors: Unhandled Rejection: Error: 500:undefined|undefined:undefined
err: Microsoft.Exchange.Data.Storage.TenantAccessBlockedException
esrc: StartupData
et: ServerError
estack: Error: 500
   Information deleted for privacy protections/Information deleted for privacy protection
st: 500
ehk: Information deleted for privacy protection
efe: Information deleted for privacy protection
ewsver: Information deleted for privacy protection
emsg: TenantAccessBlockedError

Answer 1

Hi @Josh Kolasinski,

Thank you for posting your question in the Microsoft Q&A forum.I would like to provide you with the following information:

This error occurs when your account is unable to connect to the Microsoft 365 tenant.

The error you are encountering — TenantAccessBlockedException — typically occurs when a Microsoft 365 tenant is blocked at the organization level. This can happen in the following scenarios:

• Your Microsoft 365 subscription has been temporarily suspended due to an expired domain, a billing issue, or outstanding unpaid charges; or
• You have recently renewed your domain, but the changes have not yet been fully synchronized across Microsoft’s internal systems (this process can take up to 24 hours).

Because this is a tenant-level blocking issue, only a Global Administrator (Global Admin / IT Admin) for Microsoft 365 can resolve it. Standard users cannot fix this issue by reinstalling applications, clearing cache, or changing local settings.

To proceed, please ask your Global Administrator to perform the following steps:

1. Check and resolve billing-related issues

• Sign in to the Microsoft 365 admin center
• Go to Billing > Billing and payments and settle any outstanding balances
• Then navigate to Billing > Your products, select the Microsoft 365 or Exchange Online subscription, and check its status

If the subscription status shows Suspended or Deactivated, select Reactivate subscription and follow the on-screen instructions (including updating the payment method if required).

If you have already confirmed that your billing information is fully valid, you may skip Step 1 and continue with the steps below.

Note: After completing payment or reactivating the subscription, Microsoft may require 1–3 hours (up to 24 hours) to fully restore the service. During this time, you may continue to see the following error:

“Tenant is blocked with Microsoft.Exchange.Data.Storage.TenantAccessBlockedException.”

2. Use PowerShell to verify and unblock the account

The Global Administrator can run the following PowerShell commands:

Check the status of SKUs (licenses):

Connect-MsolService
Get-MsolAccountSku

Unblock a user account (if the individual account is blocked):

Set-MsolUser -UserPrincipalName ******@domain.com -BlockCredential $false
 

This command will unblock the user in cases where the individual account has been blocked from signing in.

 

If it has been confirmed that the tenant is on hold or suspended, but the issue cannot be resolved through the admin portal, the administrator should open a support ticket with Microsoft Support. A support engineer may:

• Initiate a remote support session to investigate the issue in detail
• Verify backend configurations
• Run necessary synchronization tools
• Escalate the case to specialized teams if deeper investigation is required

Note: The steps below require tenant administrator privileges.

• Step 1: Go to admin.microsoft.com
• Step 2: Select Help & Support
• Step 3: Enter the title: Request assistance to unblock tenant / account
• Step 4: Select Contact Support
• Step 5: Choose your preferred contact method

Once the ticket is received and assigned to a support engineer, the agent will proactively contact you and work directly with you to investigate and resolve the issue.

 I hope this information is helpful. Please follow these steps and let me know if it works for you. If not, we can work together to resolve this.   

Thank you for your patience and your understanding. If you have any questions or need further assistance, please feel free to share them in the comments on this post so I can continue to support you.

I look forward to continuing the conversation./

---

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment". 

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread. 

Answer 2

The error Microsoft.Exchange.Data.Storage.TenantAccessBlockedException / TenantAccessBlockedError with HTTP 500 during Outlook startup indicates that access to the Microsoft 365 tenant is being blocked at the service side. This is not a client configuration or profile issue in Outlook for Windows; it is a server-side condition in Exchange Online.

Because the tenant is blocked, Outlook cannot complete startup and load mailbox data, which results in the 500 server error and the TenantAccessBlockedError in the log.

Required action:

1. Contact the Microsoft 365 administrator for the organization.
2. From the Microsoft 365 Admin Center, the admin must open a support case with Microsoft.
3. Exchange Online support needs to investigate why the tenant is blocked and remove or mitigate the block. This is the only way to resolve this class of error; client-side repairs or reinstalls will not fix it.
4. As a temporary workaround while the tenant block is being resolved, use Outlook on the web (OWA) or classic Outlook/new Outlook only if and when the tenant block has been lifted. While the tenant remains blocked, all clients will be affected.

---

References:

• Error when opening classic Outlook: "Cannot start Microsoft Outlook. Cannot open the Outlook window. The set of folders cannot be opened. The attempt to log on to Microsoft Exchange has failed."