RSS FEED WON'T WORK

Hi my site http://www.howtoovercomeanxiety.net/feed

is showing a problem with my feed and it is saying that my homepage cannot be found?

It will not display any feed and also when i try to setup a feed of my site using a feed plugin this also shows a error.

I have also tried to validate my feed and it says not valid

and gives this error: Server returned HTTP Error 404: Not Found

Hope someone can help with this as i have tried everything to get this sorted.

I am using the thesis theme.

Thanks
will