I am having the same issue with not being able to connect to the update server. However, I can send a test email and can also ping the update server.
root@VLfreenas2[~]# ping update-master.ixsystems.com
PING update-master.freenas.org (38.126.124.199): 56 data bytes
64 bytes from 38.126.124.199: icmp_seq=0 ttl=45 time=173.828 ms
64 bytes from 38.126.124.199: icmp_seq=1 ttl=45 time=173.957 ms
64 bytes from 38.126.124.199: icmp_seq=2 ttl=45 time=173.697 ms
Any help please?