Forum Discussion
Guest users do not receive Office Group conversations
'OtherMails' is an attribute managed by Azure AD afaik, you cannot change it via the Exchange cmdlets. You should be able to change it via Set-MsolUser/Set-AzureADUser or the Graph API directly, but I'm not sure if such changes later flow to ExO. They should I suppose, so give it a try.
It's exactly the same attribute, I've confirmed that changing it in Azure AD updates it in Exchange Online after I posted yesterday. In your case it probably got out of sync, so you can try setting it on Azure AD side and wait for synchronization to occur.
I set it on Azure AD side and now when I run Get-AzureADUser I get Provisioning Error:
I tried to wait for synchronization (2 days) but the provisioning error still occurs.
Could you advise something? Should I wait longer for synchronization?
As the error message suggests, you seem to have another object to which this address is already assigned, which probably explains the initial "empty" value. Try to locate said object by running
Get-Recipient email@domain.com
Or open a support case.