Thursday, July 31, 2008

500 Internal Server Error when using OWA with /Exchange

You get this 500 - Internal Server error while you access Outlook Web Access from https://CASServer.domainname.com/exchange while https://CASServer.domainname.com/owa works fine.
This happens when you have seperate Exchange 2007 Mailbox and CAS servers. Ideally the request should be redirecetd to /owa but you get 500 - Internal Server Error right after typing in your credentials in the forms login page.

This happens due to the fact that redirection is not working because ISAPI Extensions are not installed on the Mailbox Server. ISAPI extensions handle specific incoming requests to the IIS server. Extensions are loaded when they are first needed and kept in memory until the host process shuts down.

To fix this issue, please install the ISAPI Extensions on the mailbox server.

Here is the command that you have to run from the EMS to install them:

ServerManagerCmd -i Web-ISAPI-Ext

Make sure to do an IISRESET after this.

2 comments:

Running Around Acres said...

Can this happen with E2k3 as well? We do not use https - only http. But we do get the internal error or it will return the internal FQDM of the server.

Randeep Singh Sahota said...

If you have this error on Exchange 2003, then it could possibly be linked to your back end being a cluster..
This is detailed in:
http://support.microsoft.com/kb/841561

Thanks