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  • The HTTP request is unauthorized with client authentication scheme 'Anonymous'

    Oct 17, 2018 03:06 AM|Shakhil Srivastava|LINK

    We have a set of VMs (windows server 2016) hosting IIS 10 with an Asp.Net based website. The website connects to a third party asmx based web service. Recently when connecting to the web service we have been receiving this error called

    "The HTTP request is unauthorized with client authentication scheme 'Anonymous'. The authentication header received from the server was 'Negotiate,NTLM'".

    The error is occurring very intermittently and sometimes it goes away automatically appearing the next day again. We tried switching off the auto recycling of the IIS Application pool, but that didn't help. What is more interesting is, we have other similar VMs for test environments with exactly the same configurations and settings, even hosting the same code which never encounters this error. The website uses Windows Authentication while the service is using Client Credentials (Username and password) to authenticate. IIS logs on the website shows status 200. Changing the config file may not be a solution as the same config file is working on other servers connecting to the same service. Anyone got any idea, please suggest.

    Thanks

    Shakhil Srivastava