New Exchange 2013 can receive ok but will not send mail to the internet

Hi All,

I've recently installed EX2013 and when I tested mailflow I can send mail into our EX2013 mailboxes but for some reason I 

18/01/2016 10:56:35 - Remote Server at gmail.com (2404:6800:4008:c01::1a) returned '550 4.4.7 QUEUE.Expired; message expired'
18/01/2016 10:43:01 - Remote Server at gmail.com (2404:6800:4008:c01::1a) returned '441 4.4.1 Error encountered while communicating with primary target IP address: "Failed to connect. Winsock error code: 10065, Win32 error code: 10065." Attempted failover to alternate host, but that did not succeed. Either there are no alternate hosts, or delivery failed to all alternate hosts. The last endpoint attempted was 2404:6800:4008:c01::1a:25'

Any help will be greatly appreciated it.

Thank you.