I had the same one from him last year and the beginning of the year. They had his tour dates on it...I never really heard anything back from those, so I tried snail mail and it worked.

The auto-reply will just be letting you know that your email has been received and it will be read in due time.
If there has been successes using the address before then there is a good chance you will get a success also. You just need to give the email time to be read.

I got an auto-reply. Should I be worried? Or do you think a signed photo will still be sent out? I got the address from a success.