Exchange 2013 - RCA reports RPC Proxy can't be pinged (404)

Hi, I've searched extensively and spent hours trying to fix my problem and nothing in the forums has addressed yet. 

I have a new exchange server 2013 SP1 and Outlook 2013 clients can't connect. Outlook states Exchange Server is Unavailable. 

This led me to Microsoft RCA. RCA reported that the RPC Proxy can't be pinged with a 404 error. But I CAN visit the server RCA references a step or two above and am treated to a white page, no 404. ( https://xch.domain.com/rpc/rpcproxy.dll?xch.domain.com:6002 )

I have set ExternalAuthenticatoin to Negotiate and internal to NTLM, I have set outlookProvider to 

[PS] C:\Windows\system32>Get-Outlookprovider

Name                          Server                        CertPrincipalName             TTL
----                          ------                        -----------------             ---
EXCH                                                        msstd:*.domain.com       1
EXPR                                                        msstd:*.domain.com       1
WEB                                                                                      1

The SSL Certificate is a trusted one, the External URL is set properly in the server settings via ECP as well.

Any ideas would be greatly appreciated. I'm tired and incapable of listing all of the steps I've tried, but if you know of any tips for troubleshooting and fixing RPC Ping issues, I would love to hear them. 

Thanks!