I have a department that has a public folder for receiving Customer Service emails. They wanted to be able to send emails to customers using the email address on the public folder. I have given them send as permissions. They use the From field to put in the email address of the group and it seems to work find except for one user. When she tries she gets a "you don't have permission to send on behalf of this user". She is the same as everyone else in Exchange.
We are using Outlook 2007 and Exchange 2007.