I know this is a very vague question.
I want to deep dive into this question
Scenario 1: User A has send as access to the shared mailbox. But when User A tries to send email to from the Shared mailbox
This is what User A does click- New email - options -from - select the shared mailbox name and tries to send an email and he gets an undeliverable message.
This message could not be sent. Try sending the message again later, or contact your network administrator. You do not have the permission to send the message on behalf of the specified user. Error is [0x80070005-0x0004dc-0x000524].
When I gave him the send as access why is it throwing the error that the user doesnot have send on behalf of permission.
Scenario 2: User B migrated to exchange online tries to send email from the shared mailbox he has (send as) access and get an message failure that (shared mailbox is on premise)
You don't have permissions to send on behalf of the specified user.
please can some one elaborate on what is going on?