C# – Could not load file or assembly System.Web.Http.WebHost

I'm running my application on an IIS server, but now I want to do some debugging with breakpoints etc, so I decided to run from Visual Studio to IIS Express. But, when I start running my application I receive this error:

Server Error in '/' Application.

Could not load file or assembly 'System.Web.Http.WebHost,
Version=5.2.3.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or
one of its dependencies. The located assembly's manifest definition
does not match the assembly reference. (Exception from HRESULT:
0x80131040)

Description: An unhandled exception occurred during the execution of
the current web request. Please review the stack trace for more
information about the error and where it originated in the code.

Exception Details: System.IO.FileLoadException: Could not load file or
assembly 'System.Web.Http.WebHost, Version=5.2.3.0, Culture=neutral,
PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The
located assembly's manifest definition does not match the assembly
reference. (Exception from HRESULT: 0x80131040)

Source Error:

Line 13:
Database.SetInitializer(new
TodoListServiceInitializer()); Line 14:
GlobalConfiguration.Configure(WebApiConfig.Register); Line 15:
} Line 16: } Line 17: }

Source File:
C:\develop\spl_development\main\Docks\Docks_Sensor\Global.asax.cs
Line: 15

Assembly Load Trace: The following information can be helpful to
determine why the assembly 'System.Web.Http.WebHost, Version=5.2.3.0,
Culture=neutral, PublicKeyToken=31bf3856ad364e35' could not be loaded.

=== Pre-bind state information === LOG: DisplayName = System.Web.Http.WebHost, Version=5.2.3.0, Culture=neutral,
PublicKeyToken=31bf3856ad364e35 (Fully-specified) LOG: Appbase =
file:///C:/develop/Spl_Development/Main/Docks/Docks_Sensor/ LOG:
Initial PrivatePath =
C:\develop\Spl_Development\Main\Docks\Docks_Sensor\bin Calling
assembly : Docks.Sensor, Version=1.0.0.0, Culture=neutral,
PublicKeyToken=null.
=== LOG: This bind starts in default load context. LOG: Using application configuration file:
C:\develop\Spl_Development\Main\Docks\Docks_Sensor\web.config LOG:
Using host configuration file:
C:\Users\ligthart\Documents\IISExpress\config\aspnet.config LOG: Using
machine configuration file from
C:\Windows\Microsoft.NET\Framework\v4.0.30319\config\machine.config.
LOG: Post-policy reference: System.Web.Http.WebHost, Version=5.2.3.0,
Culture=neutral, PublicKeyToken=31bf3856ad364e35 LOG: Attempting
download of new URL
file:///C:/Windows/Microsoft.NET/Framework/v4.0.30319/Temporary
ASP.NET Files/vs/25aafd2f/29cb2bd3/System.Web.Http.WebHost.DLL. LOG:
Attempting download of new URL
file:///C:/Windows/Microsoft.NET/Framework/v4.0.30319/Temporary
ASP.NET
Files/vs/25aafd2f/29cb2bd3/System.Web.Http.WebHost/System.Web.Http.WebHost.DLL.
LOG: Attempting download of new URL
file:///C:/develop/Spl_Development/Main/Docks/Docks_Sensor/bin/System.Web.Http.WebHost.DLL.
WRN: Comparing the assembly name resulted in the mismatch: Build
Number ERR: Failed to complete setup of assembly (hr = 0x80131040).
Probing terminated.

Stack Trace:

[FileLoadException: Could not load file or assembly
'System.Web.Http.WebHost, Version=5.2.3.0, Culture=neutral,
PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The
located assembly's manifest definition does not match the assembly
reference. (Exception from HRESULT: 0x80131040)]
Docks.Sensor.WebApiApplication.Application_Start() in
C:\develop\spl_development\main\Docks\Docks_Sensor\Global.asax.cs:15

[HttpException (0x80004005): Could not load file or assembly
'System.Web.Http.WebHost, Version=5.2.3.0, Culture=neutral,
PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The
located assembly's manifest definition does not match the assembly
reference. (Exception from HRESULT: 0x80131040)]
System.Web.HttpApplicationFactory.EnsureAppStartCalledForIntegratedMode(HttpContext
context, HttpApplication app) +9966013
System.Web.HttpApplication.RegisterEventSubscriptionsWithIIS(IntPtr
appContext, HttpContext context, MethodInfo[] handlers) +118
System.Web.HttpApplication.InitSpecial(HttpApplicationState state,
MethodInfo[] handlers, IntPtr appContext, HttpContext context) +172
System.Web.HttpApplicationFactory.GetSpecialApplicationInstance(IntPtr
appContext, HttpContext context) +352
System.Web.Hosting.PipelineRuntime.InitializeApplication(IntPtr
appContext) +296

[HttpException (0x80004005): Could not load file or assembly
'System.Web.Http.WebHost, Version=5.2.3.0, Culture=neutral,
PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The
located assembly's manifest definition does not match the assembly
reference. (Exception from HRESULT: 0x80131040)]
System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +9947380
System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context)
+101 System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest
wr, HttpContext context) +261

Version Information: Microsoft .NET Framework Version:4.0.30319;
ASP.NET Version:4.6.1055.0

I've seen a lot of questions, but can't really seem to find an answer to this problem. I went looking if any of the required files or references were missing.. but no:

References: