Forum Discussion
SMTP-addresses not in sync with AD
You should be able to use the -WindowsEmailAddress parameter for this. The new address you specify should be set as the Primary SMTP, while the old primary one will be kept as secondary. The cmdlet will also work against synced users.
If that's not a viable solution for your scenario, you can force-delete the mailbox in O365 and provision the object anew. Use the method outlined here for fastest resolution: https://blogs.technet.microsoft.com/exchange/2018/01/17/permanently-clear-previous-mailbox-info/
How did you remove the online mailbox? Please refer to the following:
https://technet.microsoft.com/en-us/library/jj863440(v=exchg.160).aspx
Then you can add SMTP:user@domain.com in ProxyAddresses property of local AD. Note that it can take some time to appear in the online user (more tan a sync cycle)
- I just disabled the Licence of "Exchange Online". In local AD the property is set correct, so adding is not possible. I also tried to remove the adress in local Exchange, sync and add it again. Didn't work.
By disabling the license you are not removing the mailbox
Please refer to the article I posted in order to permanently delete EXO mailbox
