Trouble with Sender Address in Campaigsn

Trouble with Sender Address in Campaigsn

Hi,
For some reason I cannot change the Sender Adress of my email campaign. Even though I enabled  the privilege under Settings tab —>Manage Users —>Privilege —>Use Sender/Reply to Address —>All users -->Save, no changes. It only shows my email address as an option and as soon as I try to enter another address (info@...) it gives me this error, see screen shot