ASP.NET session state not being shared in Redis

Question

We are planning to migrate from ASPstate to Redis to store session. We installed the Redis MSI package on one of the servers and the c# application is hosted on a different server. We have multiple web applications within single application hosted in IIS.

The configuration for both applications looks like this:

<sessionState mode="Custom" customProvider="MySessionStateStore" timeout="180">
    <providers>
        <add name="MySessionStateStore" 
             type="Microsoft.Web.Redis.RedisSessionStateProvider" 
             host="serverIP"
             port="6379"
             accessKey=""
             ssl="false"
        />
    </providers>
</sessionState>

Now the problem is that session is not being shared between applications. We checked the machine key and found to be same both applications.