Issue logging into outlook

Question

Getting below error while logging into outlook via web

err: CannotResolveExternalDirectoryOrganizationIdException

esrc: StartupData

et: ServerError

estack: Error: 401

email Id - [Moderator note: personal info removed]

Moved from: Outlook | Web | Outlook.com | Email

Answer 1

Dear @Surojit Dutta,

Thank you for posting your question in the Microsoft Q&A forum.

I understand how frustrating this is, especially when you’re unable to access Outlook at all. In this case, this specific error (CannotResolveExternalDirectoryOrganizationIdException) usually means that Outlook on the web cannot find an active Exchange Online mailbox for your account.

First, I recommend you try clear your browser cache and cookies and logging in again. Then, test with a different network

If the issue still persists and you are user, I highly recommend you reach out to your IT Admin/Microsoft 365 administrator to confirm that your account has an Exchange Online license assigned and fully provisioned. For reference, your IT Admin can refer to this: Assign or unassign licenses for users in the Microsoft 365 admin center

Note: If you do not know your Admin, please refer to this Microsoft article: How do I find my Microsoft 365 admin?

If the license is already assigned, I recommend that your admin unassign and then reassign the Exchange Online license. This helps trigger mailbox reprovisioning on the backend, which often resolves this issue.

• Sign in to Microsoft Admin Center with a Global admin. Open Users > Active users. Select the user you created. Open Licenses and apps, then assign any plan that includes Exchange Online such as Microsoft 365 Business Basic or Standard, Office 365 E3, Microsoft 365 E3 or E5, or Exchange Online Plan 1 or 2. Save.
• Back on the user page, look for the Mailbox section and confirm it shows as active. Now open a private browser window and go to https://outlook.office.com and sign in with that user.

If your tenant does not have any Microsoft 365 or Exchange Online subscription yet, ask your admin to start a trial in the Microsoft 365 admin center first and then assign it to the user. For refernece: Try or buy a Microsoft 365 for business subscription

Note: Please understand that as a forum moderator, my role is to provide general guidance and troubleshooting support. I don’t have access to internal systems or backend tools, and I appreciate your understanding of these limits.

I hope the information shared helps point you in the right direction. Please try the steps above and let me know if they work. If not, we can continue working together to narrow this down.

The first response may not always resolve the issue right away, but with your help and more details, we can work toward a solution.

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

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