OWA 2003 503 Service Unavailable

[cmillerl]

We have a front-end and a back-end Exchange 2003 server, both inside a firewall. I've set up OWA 2003 on the front-end with forms-based authentication/SSL. It was working fine for a couple of months. Last Friday, I decided to edit the logon.asp page and make a few simple changes. The first change worked great, but after making the second change the OWA logon.asp page wouldn't come up. I replaced the modified logon.asp page with the original and it seemed to be working okay; however, although the logon page came up I didn't attempt to login in. On Monday, I found out the users are getting an HTTP/1.1 503 service unavailable message after entering the domain\userid and password. I've looked through MSKB 823159, and everything it mentioned checks out okay. I'm not getting any strange event ids. I've looked at the IIS logs and the only thing I've noticed is that sometimes when I first enter the address I'm getting a message stating that my userid and/or password were incorrect even though I haven't entered either yet or clicked on the button to submit them. I've stopped and restarted IIS, I've copied the logon.asp over from my back end server. No luck. Here's an excerpt from the IIS logs:

2005-01-18 15:55:59 172.16.1.11 GET /exchange - 443 - 172.16.1.15 Mozilla/4.0+(compatible;+MSIE+6.0;+Windows+NT+5.0) 302 0 0
2005-01-18 15:55:59 172.16.1.11 GET /exchweb/bin/auth/owalogon.asp url=https://FEServer.osuf.org/exchange&reason=2 443 - 172.16.1.15 Mozilla/4.0+(compatible;+MSIE+6.0;+Windows+NT+5.0) 200 0 0
2005-01-18 15:56:14 172.16.1.11 POST /exchweb/bin/auth/owaauth.dll - 443 - 172.16.1.15 Mozilla/4.0+(compatible;+MSIE+6.0;+Windows+NT+5.0) 200 0 0
2005-01-18 15:56:15 172.16.1.11 GET /exchange - 443 MyDomain\myid 172.16.1.15 Mozilla/4.0+(compatible;+MSIE+6.0;+Windows+NT+5.0) 503 0 0
2005-01-18 15:57:38 172.16.1.11 GET /exchange - 443 - 172.16.1.15 Mozilla/4.0+(compatible;+MSIE+6.0;+Windows+NT+5.0) 401 2 2148074254
2005-01-18 15:57:38 172.16.1.11 GET /exchweb/bin/auth/owalogon.asp url=https://FEServer.osuf.org/exchange&reason=0 443 - 172.16.1.15 Mozilla/4.0+(compatible;+MSIE+6.0;+Windows+NT+5.0) 200 0 0
2005-01-18 15:57:46 172.16.1.11 POST /exchweb/bin/auth/owaauth.dll - 443 - 172.16.1.15 Mozilla/4.0+(compatible;+MSIE+6.0;+Windows+NT+5.0) 200 0 0
2005-01-18 15:57:47 172.16.1.11 GET /exchange - 443 MyDomain\myid 172.16.1.15 Mozilla/4.0+(compatible;+MSIE+6.0;+Windows+NT+5.0) 503 0 0

I'm stuck - not sure where to look. I'd really appreciate ideas on what to look at next! Thanks.

 

[cmillerl]

I'm now wondering if one of the MS patches I applied to this server on Sunday morning is causing this. I applied 891711, 890175, 885385, 833987. Has anyone applied these patches to an Exchange 2003/OWA 2003 server that uses SSL?