Error 500 when attempting to login to outlook

Question

Error 500 when attempting to login to outlook

m 0

Trying to login to outlook for the first time on this account, and receive this error log:

UTC Date: 2026-11-05T23:43:51.536Z
Client Id: 
Session Id: 
Client Version: 20261030007.14
BootResult: configuration
Back Filled Errors: Unhandled Rejection: Error: 500:undefined|undefined:undefined
err: Microsoft.Exchange.Clients.Owa2.Server.Core.OwaUserHasNoMailboxAndNoLicenseAssignedException
esrc: StartupData
et: ServerError
estack: Error: 500
st: 500
ehk: X-OWA-Error
efe: 
ewsver: 
reqid: 
cv:

clearing cache, using incognito mode, swapping browsers, even swapping devices doesnt fix the issue. I will add that i accidentally added a backslash () to the box requiring the code via text or voicemail(not sure what to call it) and the site accepted it anyway, not sure if that is the root cause of the problem

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1 answer

Your answer

Answer 1

Dear m,

The error "OwaUserHasNoMailboxAndNoLicenseAssignedException" appears to mean that the account you signed in with has no Exchange Online mailbox and no license that includes Exchange Online. This is checked on the service side after sign-in. That would explain why changing the browser or device didn't help.

In this case, please contact your IT admin to do these steps below:

Go to the Microsoft 365 admin center > Users > Active users and select your account.
Open Licenses and apps.
Make sure a license that includes Exchange Online is assigned. Expand Apps and confirm Exchange Online is ticked.
Select Save changes.

If the license was assigned recently, please allow time for the mailbox to be created. This usually takes under 30 minutes but can sometimes take up to 24 hours. Then sign in to Outlook on the web again in a new InPrivate window.

If the license is already assigned and Exchange Online is enabled, the admin can untick Exchange Online, save, tick it again, save, and wait for the sync. Please only do this for a new account that has no mailbox data yet.

Untitled

You may also refer to: Getting a mailbox not found error in Outlook on the web - Microsoft 365 admin | Microsoft Learn.

I hope this helps. Please feel free to reply below if you have any update or further concern.

Looking forward to your response!

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