If you are having trouble sending email to an aol email address here are a few things you may want to try. The specific error that we were receiving was:

Your message has encountered delivery problemsto the following recipient(s):

http://postmaster.info.aol.com/errors/554rlych.html
554 TRANSACTION FAILED

Sent: (message data)
Received:554-: (RLY:CH) http://postmaster.info.aol.com/errors/554rlych.html554 TRANSACTION FAILED

With AOL there is a lovely report spam button that you can use when you feel that a message you receive is a spam email message. If you get enough complaints then you will start getting these return messages when you send to any of the aol.com domains. The person in question had a virus on their PC an so they were blacklisted by aol. I was surprised to be greeted with absolutely no hold time when I called their postmaster phone number (888)-212-5537. It has been a while since I picked up a phone to contact AOL and I must say the experience was overall a good one. The representative was extremely helpful. The IP address that the client had did not show in their records so the representative provided me with an email address that will return the IP address that AOL is seeing. If you sent an email to ipconfirm@postmaster.aol.com, then you will get a response back with the guilty IP address. You will have to send the email to the ipconfirm address from the computer that the emails are being returned to or through the email server that they are being returned to. The representative at the number was nice enough to go ahead and remove it from their list, but suggested setting up a feeback loop going forward. The feedback loop will kick you an email anytime they get an email you send that one of their members designates as spam. This can be very helpful if you have a mail server and have one party that is sending out spam mail.

More AOL Email Troubleshooting tips can be found at the following URL: http://postmaster.info.aol.com/trouble/

Ran into a problem where a Vista machine joined to our corporate domain would not allow you to logon to Live Messenger. If the same machine was taken outside the office it would connect without problem. SO after searching and searching, upgrading to the Beta 8.1 (Still did not work), found a solution that worked.

Try this:
- Click start
- Type: cmd
- Right-click cmd.exe when it appears under Applications
- Click Run As Administrator
- Type the following: netsh int tcp set global autotuninglevel=disabled
- Press enter
- Restart your computer

To check autotuning is disabled repeat the above but type: netsh int tcp
show global

This worked for me when all other fixes and work-arounds did not.

Hope it helps someone else!