HI zhang baobing,
It seems like you have network connection problem at your place.
1. Make sure you can able to ping the server without any packet loss -
$ ping commondatastorage.googleapis.com
PING commondatastorage.googleapis.com (216.58.203.16) 56(84) bytes of data.
64 bytes from bom12s04-in-f16.1e100.net (216.58.203.16): icmp_seq=1 ttl=111 time=77.3 ms
64 bytes from bom12s04-in-f16.1e100.net (216.58.203.16): icmp_seq=2 ttl=111 time=73.2 ms
^C
--- commondatastorage.googleapis.com ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1002ms
rtt min/avg/max/mdev = 73.292/75.319/77.347/2.045 ms
$
2. If ping fails then check your connectivity
3. If connectivity is ok, check with your administrator if they have mistakenly set any firewall rule to block.
Regards,
Radhika Somaiya