Problems sending/receiving

Hi guys,

I've spent way too long on this and I'm hoping someone can help me out.

A couple of days ago I thought I'd have a crack at installing CU1 on my 2013 server (around 12pm). It failed and it looked like I stopped receiving mail. I was however still 'connected to exchange'. I later realised that no mail was received after about 2pm that day.

I restored the entire server back to 7am that morning when I knew that the system was running fine. Strangely enough systems still aren't working.

I can connect to OWA/ECP and log in fine. I see my mail up until 2pm.

I can send email from OWA yet it doesn't appear in my outbox or sent items not does it appear in the exchange queue.

Outlook on domain computer says disconnected (Kerberos?) but my Outlook on my external computer says connected (basic authentication).

There are only 2 servers (Exchange and AD) and I've now changed our outgoing mail server and MX records so that mail doesn't pass through our spam filter.

Here's what I've done:

checked MX records

Removed port forward (all outbound traffic allowed) and re-added

Tested with remote connectivity analyser and got the following:

Testing TCP port 25 on host mail.domain.com.au to ensure it's listening and open.
	The specified port is either blocked, not listening, or not producing the expected response.
	Additional Details   The connection was established but a banner was never received. Elapsed Time: 16673 ms.

Any help would be awesome! Thanks