Log into the server where you have WordPress and FWP installed by SSH. The ping the not found servers. For example:
ping yahoo.com
That would be the first step to make sure your server can communicate and find the DNS for those not found sites. I had this issue once before.
I have now 4 blogs where this error occurs constantly.
2 of them are wordpress blogs hosted on wordpress.com and 2 are blogspot blogs hosted on blogspot.*
http://chalicecarling.blogspot.de/feeds/posts/default
http://beatriceserendipity.blogspot.co.uk/feeds/posts/default
http://untouchablelife.wordpress.com/feed/
http://josiedecuir.wordpress.com/feed/
As I don’t have problems with other blogs hosted on wordpress or blogspot this really puzzles me.
I tried the ping and ping works from the server on all 4 blogs
Ok, finally I found the solution. I’m posting it, if someone else has the same problem.
I had the chance to get admin rights for one of the blogs and checked the settings and played around.
It seems to be a timeout problem. It occurs for blogs with large feeds. E.g. both wordpress blogs had set the maximal amount of posts for the feed to 50. Reduced to 30 I could syndicate the blogs without problems.
On blogspot there seems to be now way to reduce length of the feed in the settings. Here another trick helps:
Instead of trying to enter the following address in the syndicate field
http://myblogname.blogspot.com/
or
http://myblogname.blogspot.com/feeds/posts/
reduce the feed manually:
http://myblogname.blogspot.com/feeds/posts/default?max-results=10
and all works.
