Error – We are preparing a mailbox for the user..
After assigning a license to Microsoft 365 user, you don’t see mailbox of user and see below error on the portal, under email section.
“We are preparing a mailbox for the user”
To resolve the issue, you can follow below steps.
- Just remove license from user and wait for some time, re-assign the license. If you still don’t see mailbox, move to next step.
- Under the Health -> Service Health -> Check if there is any incident reported for you tenant.
- If not, Please run the below command and see if there is any error for the user and any service incident related to that.
- Get-MsolUser -UserPrincipalName UserWithError@domain.com | select -ExpandProperty Errors
- If you see error with user, you can run the below command to get the exact error for the user.
Get-MsolUser -UserPrincipalName UserWithError@domain.com | ft UserPrincipalName,@{Name="Error";Expression={($_.errors[0].ErrorDetail.objecterrors.errorrecord.ErrorDescription)}} -AutoSize -wrap - In the error report you will find out the user and see the error, for any conflicting attribute, for example UPN or Country Code, etc.
- If you Sync the attributes from On-prem AD, you can correct the attribute there or match the attribute with any healthy account to see the difference.
- Once done, run an AD Sync Cycle and see if that resolve the issue.
- If the issue is still not solved, you will have to log a case with MS support.
Get-MsolUser -HasErrorsOnly -All | ft DisplayName,UserPrincipalName,@{Name="Error";Expression={($_.errors[0].ErrorDetail.objecterrors.errorrecord.ErrorDescription)}} -AutoSize -wrap
Get-MsolUser -HasErrorsOnly | select DisplayName,UserPrincipalName,@{Name="Error";Expression={($_.errors[0].ErrorDetail.objecterrors.errorrecord.ErrorDescription)}} | Export-csv c:tempvalidationerrors.csv 
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