Exchange 2013 ECP/OWA/Outlook all failing - 503 Service Unavailable

My exchange server is really suffering at the moment. I do not know what has happened but when I connect via https (ECP/OWA) or via outlook (with in the network) I get 503 errors on ECP/OWA and Disconnected/Trying to connect in Outlook. I assume it is the same issue for both.

I think Exchange itself is OK, because I can use IMAP to send/receive emails. So I think it is something to do with the IIS configuration.

I get the 503 error when I log in. I get the log in page, but after logging in (correct username/pwd) then I get a blank screen with the error in the console (chrome browser). The only thing I have done today was to try a new SSL certificate, but had issues with the internal domain and external domain. I have put the SSL certificate for IIS Default site back to "Microsoft Exchange" However, it was all working when I finished this. I tested two client machines to ensure it was working.

The app pools all seem correct and are running under local admin. I have tried swapping the certificates back again, just in case, but no effect.

I am now very much at a loss.

Here is some of the IIS log:
2015-07-22 23:04:36 RPC_IN_DATA /rpc/rpcproxy.dll;&RequestId=1e098a25-e9c7-4229-b6b8-7aeb35633d87&cafeReqId=1e098a25-e9c7-4229-b6b8-7aeb35633d87; 443 - MSRPC - 401 1 2148074254 1 2015-07-22 23:04:36 RPC_OUT_DATA /rpc/rpcproxy.dll;&RequestId=4c1a6653-5f3b-4485-b4e2-03e59dc533be&cafeReqId=4c1a6653-5f3b-4485-b4e2-03e59dc533be; 443 - MSRPC - 401 1 2148074254 3 2015-07-22 23:04:36 RPC_OUT_DATA /rpc/rpcproxy.dll;&RequestId=4c22cf89-4716-4ff2-b509-1abc2e7454b8&cafeReqId=4c22cf89-4716-4ff2-b509-1abc2e7454b8; 443 RBC\bates MSRPC - 503 0 64 44 2015-07-22 23:04:36 RPC_IN_DATA /rpc/rpcproxy.dll;&RequestId=aae0ff8d-28d2-4c3d-8b76-7949291676e3&cafeReqId=aae0ff8d-28d2-4c3d-8b76-7949291676e3; 443 RBC\bates MSRPC - 503 0 64 167

This seems to be related (it is the 503 error)
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Shweta GoelCommented:

To fix 503 Service Error, please follow this link:
Joe PriorCommented:

I also found the same article which may helpful for you:

This error generally occurs if the application pool that is associated with the web application doesn't start.

To resolve this issue, follow the steps mentioned below:

In Event Viewer, view the System log to find errors from the Microsoft-Windows-WAS source. An event is frequently logged in the System log if the application pool fails to start.

If you don't find any relevant events in the System log, search for relevant entries in the HTTPERR log file. The httperr1.log file is located in the following system folder:


In the file, search on "503" to locate any relevant information about why the application pool failed. For example, you may see an entry that resembles the following:

2011-12-08 18:26:42 ::1%0 6721 ::1%0 443 HTTP/1.1 GET /owa 503 3 N/A SharePoint+Web+Services+Root

OblivionSYAuthor Commented:
Thanks for the link guys. It is not a small business server, but I will attempt to follow and see what common items I can do to try and fix this. Here is the first 503 entry in the log

2015-07-22 20:57:43 15393 443 HTTP/1.1 POST /Microsoft-Server-ActiveSync?Cmd=Sync&User=rbc%5Cibunce&DeviceId=SEC159BCB655E35F&DeviceType=SAMSUNGSMG900F 503 1 N/A MSExchangeSyncAppPool
2015-07-22 20:58:16 56918 443 HTTP/1.1 POST /Microsoft-Server-ActiveSync?Cmd=Sync&User=rbc%5Cibunce&DeviceId=SEC087F9E7D2EE1C&DeviceType=SAMSUNGSMT533 503 1 N/A MSExchangeSyncAppPool
2015-07-22 20:58:32 49566 80 HTTP/1.1 OPTIONS / 503 1 N/A MSExchangeOWAAppPool

However all App Pools say they are running. Server has been rebooted a couple of times and I have recycled these App Pools too
OblivionSYAuthor Commented:
I have resolved the issue. It was actually nothing to do with the App Pools (well not directly anyway)

It seemed the SSL certificate of the Exchange Backend Website had been removed. I re-added the SSL and it all started working again. Thanks for the help Joe - your post did suggest looking at the system log (I'd only seen application previously - it was too late trying to solve this last night) and in that log there was a clear SSL error on the port for Exchange Backend. Added the certificate and like magic it all started.

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OblivionSYAuthor Commented:
It was the certificate which caused the issue. The comment from Joe pointed me to the right log to review and was able to then see the issue clearly.
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