These errors indicate that google cannot access your feeds at this time. Mostly these errors will be displayed immediately after your move from feedburner to google feeds. And generally they will automatically disappear when you publish your first post after moving from feedburner to google feeds.
But if errors persists even after adding more then one posts, then it means that the problem is with your hosting service provider. The hosting service providers generally blocks IP addresses for security reasons. So to allow google to access you feeds you have to whitelist these two IP addresses-
If you are on shared hosting then contact the support, and ask then to add the above two IP addresses to the whitelist. Most of the shared hosting service providers will do this immediately after checking those IP’s, which’ll solve the problem.
If you are on cPanel or WHM on your VPS or Dedicated Server then you can whitelist the IP’s on your own. Simply login to the cPanel/WHM, click on ConfigServer Security&Firewall. Fill the IP address
in Allow IP address ___________ through the firewall and add to the allow file . Click Allow and Restart the firewall.
(Thanks hosticon for the trick.)
If you are on some VPS or Dedicated Server with its custom control panel, then simply access the help of the control panel and follow the instructions to whitelist the IP or use the google query,
“your hosting service provider name” whitelist IP
If you are still getting these errors then please contact google with details of your situation. You can also contact me me using the comments.
Here’s the google’s official response on this error.