Could not load file or assembly 'Newtonsoft.Json' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

When we get the above error after updating the Newtonsoft.Json library from the NuGet package manager or installing it. The solution to the problem is that first delete all the reference from the project or delete the DLL files from the project and then try to install the library again and then check. It worked for me after updating the Newtonsoft.Json library from NuGet package manager console

Update-Package Newtonsoft.Json

Or try this

 Update-Package –reinstall Newtonsoft.Json