July 14, 2014

HTTP Error 500.21 - Internal Server Error: ExtensionlessUrlHandler-ISAPI-4.0_32 bit has a bad module

HTTP Error 500.21 - Internal Server Error
Handler "ExtensionlessUrlHandler-ISAPI-4.0_32bit" has a bad module "IsapiModule" in its module list


By changing following settings with IIS and .config file, you can fix this issue.

Step: 1. Reorder the handlers in your .config file and make ExtensionlessUrlHandler-ISAPI-4.0_64bit as default.

Step: 2. Set framework version to "ASP.Net v4.0" in application pool it has assigned.

I could resolved my issue with these two changes.