Recipient isn't the expected type

Set-Mailbox fails, update "Send on behalf" exchange 2010, recipient isn't the expected type.

Issue:

When update "sent on behalf", you may face error "recipient isn't the expected type"

Cause:

"Send On Behalf" access has not been removed while disabling the mailbox, they accounts are still pointing to shared mailbox, it usually happens with migrated exchange.

Solution:

Go to AD Users & Groups

Select email account having problem

Click properties and select Attribute Editor

select PUBLIC DELEGATES and remove the mailbox account you seen in the error.