my RSS feed is not validating

For the past 18 months Aweber has been automatically sending out a weekly email broadcast of my posts for the week to my mailing list.

It hasnt happened for the past 2 weeks.

I contacted Aweber and here is what they said

“Basically there is some error with it that means that RSS readers are
not able to pull the data from it. Here’s a little more information on
the error, that hopefully they can help you resolve.
http://validator.w3.org/feed/check.cgi?url=http%3A%2F%2Fmenopauseweightloss.org%2Ffeed

Any ideas on how I can solve this would be much appreciated.

Thanks in advance

Jay