debuggingiis-7.5
Might be a n00b question.
I have an IIS server with a site where I can host our website. But if I host the same website as an application in an existing site, it gives us a 500 error.
But my question is how do I go about debugging it? Event logs show no related entries, IIS logs just show the HTTP GET messages but no errors, disabling 'display friendly http errors' does nothing, failed request trace is configured but empty.
How do I find the error?
It's a ASP.NET site
Take a look at IIS7's Failed Request Tracing feature:
Troubleshooting Failed Requests Using Tracing in IIS 7
Troubleshoot with Failed Request Tracing
The other thing I would do is tweak your <httpErrors> setting because IIS may be swallowing an error message from further up the pipeline:
<configuration>
<system.webServer>
<httpErrors existingResponse="PassThrough" />
</system.webServer>
</configuration>
If the site is written in Classic ASP then be sure to turn on the Send Errors to Browser setting in the ASP configuration feature:
And finally, if you're using Internet Explorer then make sure you've turned off Show friendly HTTP error messages in the Advanced settings (though I suspect you've done that already or are using a different browser).
Resolved this: In the file C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Config\web.config the server had this directive:
<trust legacyCasModel="true" />
I removed that, and now things run fine!
Best Answer
There is a similar question on SO Detailed 500 error message, ASP + IIS 7.5
Also check that the ASP.Net version (e.g. 1.1, 2.0 or 4) has been set correctly in the Web Site properties.