Getting Error 405 in POST and 404 in GET

I have a MVC4 WebApi project working in dev environment, but got error when deploy to production. I got httperror 405 when doing a POST, and 404 error when doing GET. I know that the problem is my route is served by the wrong module, but could not figure out what is wrong.

Here is the failed request log for POST

ModuleName DirectoryListingModule 
Notification 128 
HttpStatus 405 
HttpReason Method Not Allowed 
HttpSubStatus 0 
ErrorCode 2147942401 
ConfigExceptionInfo 
Notification EXECUTE_REQUEST_HANDLER
ErrorCode Incorrect function. (0x80070001)

Here is the failed request log for GET

ModuleName IIS Web Core 
Notification 16 
HttpStatus 404 
HttpReason Not Found 
HttpSubStatus 0 
ErrorCode 2147942402 
ConfigExceptionInfo
Notification MAP_REQUEST_HANDLER
ErrorCode The system cannot find the file specified. (0x80070002)

I have tried many solutions on the board, but none of them fix my issue. My environment is Server 2008 R2, IIS7, I reinstalled .Net 4.0 framework, MVC 4. There is no WEBDAV installed, I have in web.config. I had made sure that the appPool running in intergated mode under .net 4.0 I also made sure that all windows updates are installed.

Any idea what else I could try? Appreciate very much.

User words-like-jared provided in his comment the answer that solved this problem for me. This problem caused me hours of pain and trying several other dead ends. To help others find this solution easily, I am adding this answer so skimmers don't overlook it.