Exchange: The execution of cmdlet Set-SyncMailUser failed.

[CUCOOPE]

Hi. We have a hybrid environment and recently we've encountered a problem on converting a disabled email account to shared mailbox. It was shown this error message:

Exchange: The execution of cmdlet Set-SyncMailUser failed..; Exchange: An unknown error has occurred. Refer to correlation ID...

The mailbox was disabled on the on-prem EAC and cannot be seen on the exchange online EAC so I suspect there was a problem in it. I've found that the above error can be caused by a guid conflict between the online AAD and the on-prem server and I tried the powershell in here but when I typed

Enable-RemoteMailbox “example.user@domain.com” -RemoteRoutingAddress “example.user@domain.onmicrosoft.com” -PrimarySMTPAddress “example.user@domain.com”

, there will be an error saying that:

This task does not support recipients of this type. The specified recipient <user> is of type RemoteUserMailbox. Please make sure that this recipient matches the required recipient type for this task.

get-recipient <username> returns

Name             RecipientType
----                -------------
<Username> MailUser

I don't know where to go from now. Does anyone knows how to fix this error? Thanks.

[#2]

Hi,
Did you try the Scenario 1 ?? :
https://docs.microsoft.com/en-us/exchange/troubleshoot/user-and-shared-mailboxes/mailbox-exists-exo-...

[#3]

@Thierry Chapuisat I guess so since the cmdlet in scenario 1 is similar to what I followed in the guide. However, the cmdlet 

Enable-RemoteMailbox "user identity" -RemoteRoutingAddress "user@contoso.mail.onmicrosoft.com"

 Failed and the error

This task does not support recipients of this type. The specified recipient <user> is of type RemoteUserMailbox. Please make sure that this recipient matches the required recipient type for this task.

will be shown.

[#4]

Yo ca try to change manually the recipient type display and the remote recipient type on your local ad.
http://www.mistercloudtech.com/2016/05/18/reference-to-msexchrecipientdisplaytype-msexchrecipienttyp...

[#5 · Accepted solution]

@Thierry Chapuisat At last I hard-matched the guid between Azure and the on-prem ad.