Having the router as a named server is a problem. This is causing a loop as you router is configured to point to the pi and the pi as pointed to use the router. This likely ties to your other post .
I'm not familiar with Ubuntu, which you seem to be using, but you should change the DNS Server for your PI's network connection to use 127.0.0.1 for the pi itself or choose a DNS Server that you prefer. The router IP needs to be removed though.