All ASP.NET Web API controllers return 404

Question

I\'m trying to get an API Controller to work inside an ASP.NET MVC 4 web app. However, every request results in a 404 and I\'m stumped. :/

I have th

Answer 1

I'm a bit stumped, not sure if this was due to an HTTP output caching issue.

Anyways, "all of a sudden it started working properly". :/ So, the example above worked without me adding or changing anything.

Guess the code just had to sit and cook overnight... :)

Thanks for helping, guys!

Answer 2

I have dozens of installations of my app with different clients which all worked fine and then this one just always returned 404 on all api calls. It turns out that when I created the application pool in IIS for this client it defaulted to .net framework 2.0 instead of 4.0 and I missed it. This caused the 404 error. Seems to me this should have been a 500 error. Very misleading Microsoft!

Answer 3

Had this problem. Had to uncheck Precompile during publishing.

Answer 4

WebApiConfig.Register(GlobalConfiguration.Configuration);

Should be first in App_start event. I have tried it at last position in APP_start event, but that did not work.

Answer 5

Had essentially the same problem, solved in my case by adding:

<modules runAllManagedModulesForAllRequests="true" />

to the

<system.webServer>

</system.webServer>

section of web.config

Answer 6

Add this to <system.webServer> in your web.config:

<handlers>
    <remove name="ExtensionlessUrlHandler-Integrated-4.0"/>
    <remove name="OPTIONSVerbHandler"/>
    <remove name="TRACEVerbHandler"/>
    <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="*" type="System.Web.Handlers.TransferRequestHandler"
        preCondition="integratedMode,runtimeVersionv4.0"/>
</handlers>

Adding <modules runAllManagedModulesForAllRequests="true" /> also works but is not recommended due performance issues.