The original message was received at Wed, 28 Oct 2015 17:01:04 +0300 from 16.157.10.52 ----- The following addresses had permanent fatal errors ----- dev at openvswitch.org ----- Transcript of session follows ----- ... while talking to openvswitch.org.: 550 5.1.2 <dev at openvswitch.org>... Host unknown (Name server: host not found)