Could not load file or assembly 'System.Net.Http, Version=, Culture=neutral on IIS


I started updating some nuget packages and started getting these warnings on build with a conflict for System.Net.Http. As suggested here:

Strange issue with System.Net.Http not found

I replaced all references to System.Net.Http to use the nuget version, instead of the one bundled with Visual Studio. I then changed all redirect bindings (app.configs and web.configs) as suggested everywhere and I got things working locally. But..

When I deploy to our test server I still get the error

Could not load file or assembly 'System.Net.Http, Version=, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

I´m using net 4.7.0 and Visual Studio 2017

I searched all my configs for a ref to Version but no hits. Why does the IIS think it needs this one?

My nuget version of the System.Net.Http is 4.3.4 but the actual web.config has these lines

   <assemblyIdentity name="System.Net.Http" publicKeyToken="b03f5f7f11d50a3a" culture="neutral"/>
   <bindingRedirect oldVersion="" newVersion=""/>

Again I can build and run it locally but my server reports the error.

UPDATE: I tried adding this on my servers web.config

    <assemblyIdentity name="System.Net.Http" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
    <bindingRedirect oldVersion="" newVersion="" />

That makes the error go away! But I still dont get why i need to do this? Like why do my server think it needs to use 4.2.0?
asked on Stack Overflow Apr 8, 2019 by Jepzen • edited Apr 8, 2019 by Jepzen

2 Answers


I updated my solution to .NET Framework 4.7.2 and also made sure the server had this version installed. That solved my problems. After that i can remove the binding redirect.

answered on Stack Overflow Apr 20, 2019 by Jepzen • edited Jun 25, 2019 by Leniel Maccaferri
<bindingRedirect oldVersion="" newVersion="" />

If you can not installed .net 4.7 so remove this line in web.onfig

answered on Stack Overflow Feb 20, 2020 by Fahim Akhtar

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