The error happens when the REST methods (POST, PUT, DELETE, etc). are already registered by another application. The following entries in the  web.config helped me to overcome the issue: <system.webServer> <validation validateIntegratedModeConfiguration=“false“ /> <modules runAllManagedModulesForAllRequests=“true“> <remove name=“WebDAVModule“ /> </modules> <handlers> <remove name=“WebDAV“ /> <remove name=“ExtensionlessUrlHandler-ISAPI-4.0_32bit“ /> <remove name=“ExtensionlessUrlHandler-ISAPI-4.0_64bit“ /> <remove name=“ExtensionlessUrlHandler-Integrated-4.0″ /> <add name=“ExtensionlessUrlHandler-ISAPI-4.0_32bit“ path=“*.“ […]