Troubleshoot Internal Server Error on Windows 2012
In order to troubleshoot the issue, we will first need to get the actual error to display in the browser. To do this follow the bellow steps:
1. Add the following lines to your web.config file
Add <customErrors mode="Off" /> under <system.web>
Add <httpErrors errorMode="Detailed" /> under <system.webServer>
2. Expand the sites section in IIS > Click on the site that is having issues > Open the ASP section.
3. Expand the "Debugging properties" > set the "Send Errors to browser" to True > click "Apply".
4. Check what error is generated through the browser. Below are few scenarios:
- If the error is something like ".../ is not a valid path" - "Enable Parent Paths" should be set to True under "ASP" > "Behavior". The option is also visible in the above screenshot.
- If the error is related to database connection strings such as "Cannot connect to database" - Check the code in the file on the indicated line. The error usually indicates a problem with the connection string.
- If the error is something like "The operation should use an updateable query" - Usually this error is observed when you are using an access database and the web user doesn't have permissions. The user named "User" should have modify permissions on the access database file.
- If the error is related to ODBC, 32 bit applications should be enabled by going to Application Pools > clicking on the site's pool > Advanced Settings > Set "Enable 32 bit Applications" to True.