WordPress MU

I had my sister sign up for a blog at my service, and she used an AOL email account. Its been 10 minutes and the email with the password has still not reached her mailbox. I checked the spam folder as well. I also did a Lost password request, to no avail. I tried just now, with a gmail account, and it worked fine.

Is this MU code problem? or something else?

your host may be blocked by aol.

I've learned from experience to always put a disclaimer stating that if you use AOL, you might have problems.

Also make sure that your server/domain/ip isn't blacklisted.