IIS: Unable to make the session state request to the session state server

I have an ASP.NET MVC application that is configured to run using Web Garden. Session state mode is set to StateServer in web.config using below:

<system.web>
  <sessionState mode="StateServer" stateConnectionString="tcpip=127.0.0.1:42424" timeout="360" />
</system.web>

ASP.NET State service is running on the same machine (not remote one) so hence above ip is set to 127.0.0.1 on port 42424. It is configured as Automatic and it is always running.

And maximum worker processes for application pool is set to 4.

I often get a lot of warning messages in the event log regarding to the state server. Below the error ( Event ID 1310):

Event code: 3009 
Event message: No se pudo realizar la solicitud al servidor de estado de la sesión. Detalles: última fase='Leyendo respuesta del servidor de estado', código de error=0x8007000E, tamaño de datos salientes=0 
Event time: 05/11/2020 16:22:45 
Event time (UTC): 05/11/2020 15:22:45 
Event ID: 2e332c8f5171461e9a635a55ead92129 
Event sequence: 24813 
Event occurrence: 40 
Event detail code: 50016 
 
Application information: 
    Application domain: /LM/W3SVC/2/ROOT-2-132490528848804756 
    Trust level: Full 
    Application Virtual Path: / 
    Application Path: C:\inetpub\wwwroot\MyMvcApp\ 
    Machine name: MyServer
 
Process information: 
    Process ID: 4816 
    Process name: w3wp.exe 
    Account name: MyDomain\MyAppPoolIdentityAccount
 
Exception information: 
    Exception type: HttpException 
    Exception message: No se puede realizar una solicitud de estado de sesión al servidor de estado de sesión. Compruebe que el servicio de estado ASP.NET se ha iniciado y que los puertos de cliente y servidor son los mismos. Si el servidor se encuentra en un equipo remoto, compruebe el valor de HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\aspnet_state\Parameters\AllowRemoteConnection para asegurarse de que acepta más solicitudes. Si el servidor se encuentra en el equipo local y si el mencionado valor del registro no existe o está establecido en 0, la cadena de conexión del servidor de estado debe utilizar 'localhost' o '127.0.0.1' como nombre de servidor.

    TRANSLATED TO ENGLISH:
Unable to make the session state request to the session state server.
Please ensure that the ASP.NET State service is started and that the client and server ports are the same. If the server is on a remote machine, please ensure that it accepts remote requests by checking the value of HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\aspnet_state\Parameters\AllowRemoteConnection.
If the server is on the local machine, and if the before mentioned registry value does not exist or is set to 0, then the state server connection string must use either 'localhost' or '127.0.0.1' as the server name.
 
Request information: 
    Request URL: http://my.mvcapp.com/Wizard/MakeOrder
    Request path: /Wizard/MakeOrder
    User host address: 172.28.X.XX 
    User: MyDomain\OneUser 
    Is authenticated: True 
    Authentication Type: Negotiate 
    Thread account name: MyDomain\MyAppPoolIdentityAccount 
 
Thread information: 
    Thread ID: 67 
    Thread account name: MyDomain\MyAppPoolIdentityAccount 
    Is impersonating: False 
    Stack trace: 
 
 
Custom event details: 

I have ensured that the ASP.NET State service is started and running and that the client and server ports are the correct ones, 127.0.0.1 and 42424 respectively. Also I have the registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\aspnet_state\Parameters\AllowRemoteConnection. This key exists and it is set to 0 since the ASP.NET State service is running on the same machine (no need to set it to 1).

So, I do not understand why it is saying to check state server..... Any ideas? I have spent a lot of days googling but I am not able to solve this.