I'm using Exchange 2007. I have generic mailbox which access by 8 of staff. I had assign Send On Behalf to 3 staff for testing purposes. I'm usng EMC>generic mailbox>Mail Flow>Delivery Option and i assign Full access of Geneic mailbox to these staffs. Yesterday it is working but today, one of staff sending mail on behalf of geneic mailbox, he hot below error message.So, i removed him from Send on Behalf option and re-add back and did testing, same problem still appear.Please help: Delivery has failed to these recipients or distribution lists: Ted Bremer You are not allowed to send this message because you are trying to send on behalf of another sender without permission to do so. Please verify that you are sending on behalf of the correct sender, or ask your system administrator to help you get the required permission.

Hi,What is the output of the below commandGet-ADPermission "Mailbox" |fl Do you see the user who has been granted send on behalf rights in the output with the Extended rights listed as Send as.If not use shell to give send on behalf rights with the below command.Add-ADPermission "Mailbox" -User "Domain\User" -Extendedrights "Send As"Mahendra

when i run cmdletGet-ADPermission "Generic mailbox" | flThe ouput are:1. There are not list of 3 users who has granted Send on Benalf using ESM2. Only listed Exchange Enterprise Serves, Domain Admin, Self and etc

Hi, Please run the below command from the shell and check if the users are able to send on behalf. Add-ADPermission "Generic Mailbox" -User "Domain\User" -Extendedrights "Send As" Mahendra