Outlook cannot send: "you do not have permission to send the message on behalf of the specified user"

Exchange 2003
Outlook 2003


There is a account called "office" that is used as a common mailbox for many people to get into, and send and receive mail from.

1 of these accounts is called "user1"


User1 logs onto the workstation and network.

User1 open outlook, where the profile has been setup to go to the mailbox of "office"

I have set Exchange mailbox permission on my ex server such that the user "user1" has full mailbox access.

The credentials for "user1" allow the mailbox for "office" to open properly because I have set the permissions on the Exchange server such.

The issue is when trying to send mail, every message  bounces, and the following is the error message:  "you do not have permission to send the message on behalf of the specified user"

Now I know what the "send on behalf" feature is, its used after a user grants another user delegate rights to their mailboxes, say for example when a boss wants a secretary to send out email on behalf of him.

This however is NOT that case.  The user (user1) is actually opening up the Outlook profile of the user "office"

This was working, and now is not, i'm not sure where to look.

Any ideas?
Who is Participating?
SembeeConnect With a Mentor Commented:
Exactly what permissions do you give user accounts to this shared mailbox?

Following changes to the way Exchange handles permissions, the best practises that I use is to grant shared mailboxes Full Mailbox Access AND Send As permission.
Send As is different to Send on Behalf of and is set on the Security tab of the mailbox. If you don't see the security tab, close the properties window then choose View, Advanced Features.

Hi - you sound like you may have tried a few solutions thus far, but my initial thought is that it could be a corrupt profile.  Have you tried re-creating the profile?
citsloginAuthor Commented:

Tried that, as well as have tried on a non domain computer, so i get prompted for credentials every time (so i know exactly whats using what username/password).

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citsloginAuthor Commented:
not a fix, but i got around the problem by removing all permissions from the "office" account.

then when i launch outlook, it prompts for un/pw, and the user has to put in the "office" un/pw.

i'd rather him not to have to have that password, but its a work around for now i guess.
I'm not sure that explains it though...you're still using the same username/pw/credentials, right?
citsloginAuthor Commented:
please close
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