Got some autoresponder weirdness going on, so I thought I would check here to see if I could get some help.  Long story short, the autoresponder sometimes works and sometimes gives a "Please enter a valid return address" error.  At first, I thought it had something to do with forwarding mail and turning on the autoresponse, but I have many users who forward their mail to their personals email addresses without a problem.

I usually get around this problem by checking the "use web address as return address" box and the error goes away.  Anyone know what the exact rules are for using autoresponse?

Thanks!