Could not load file or assembly 'System.Spatial' or one of its dependencies

Changed the version details in configuration file based on DLL version present in bin folder of project having issue.

In configuration file it was referring to version 5.6.4 but I have changed to version 5.6.3 which resolved the error.

Before Change

<dependentAssembly>        <assemblyIdentity name="System.Spatial" publicKeyToken="31bf3856ad364e35" culture="neutral" />        <bindingRedirect oldVersion="0.0.0.0-5.6.4.0" newVersion="5.6.4.0" />      </dependentAssembly>

After change.

<dependentAssembly>        <assemblyIdentity name="System.Spatial" publicKeyToken="31bf3856ad364e35" culture="neutral" />        <bindingRedirect oldVersion="0.0.0.0-5.6.3.0" newVersion="5.6.3.0" />      </dependentAssembly>

if you are using visual studio, go to nugget package manager and view installed packages, and use update pane to update system.spatial package,

this solved my issue

For some reason I don't know, Visual Studio wasn't uploading newer .dll file to the server.So I manually uploaded System.Spatial version 5.7.0 on the server.

(although still I don't know how could I change the version in a so called manifest.)