When use a virtual device, cannot find pending device in the server

[yang]

hi,all
when i first attempt to use the Docker-run virtual device following the tutorial,I cannot find the the pending device in the server.
Then i check the syslog,

It seems that there is something wrong with the network，But I don’t know how to solve this problem, because Docker can ping the Internet normally,such as ping 39.156.66.10.
Some error messages also appear on the server，such as

So how to solve the problem

[yang]

I solve the problem.I can ping ip,such as 39.156.66.10,but can not ping hostname,such as ping hosted.mender.io. The reason is that the DNS server is wrong,then i change the file:/etc/resolv.conf,change the nameserver,now the virtual device can be found!