Problem using StackExchange.Redis to store to Azure hosted redis cache

Question

I can never store a string value to an Azure hosted Redis Cache. Using StackExchange.Redis version 2.0.601 and vs2015 and vs2019. Code below has error in comments (basically even with successful ConnectionMultiplexer.Connect there no connection is established).

    static bool Connect()
    {           
        ConnectionMultiplexer redis; 

        try
        {
            ConfigurationOptions cfgOptions = new ConfigurationOptions
            {
                EndPoints =
                {
                    {"RedisOnMyAzureServer", myPort}
                },
                AbortOnConnectFail = false,
                Ssl = true,
                ConnectRetry = 3,
                ConnectTimeout = 10000,
                SyncTimeout = 10000,
                DefaultDatabase = 0,
                Password = "myPassword"
            };
            redis = ConnectionMultiplexer.Connect(cfgOptions);   // takes 10.5 seconds on average 
        }
        catch
        { return false; }  // never errors

        // some diagnostics follow

        if (redis.IsConnected) 
            Console.WriteLine("client connection open"); 
        else
            Console.WriteLine("client connection closed");

        if (redis.GetDatabase().IsConnected(default(RedisKey))) 
            Console.WriteLine("database connection open"); 
        else 
            Console.WriteLine("database connection closed");

        // both connection are always closed.

        try
        {
            IDatabase db = redis.GetDatabase();
            db.StringSet("mykey", "value");
        }
        catch
        { return false; }  // always errors 

        return true;
    }

Errors at last try/catch on db.StringSet method. I get this message:

No connection is available to service this operation: SET mykey; A blocking operation was interrupted by a call to WSACancelBlockingCall; IOCP: (Busy=0,Free=1000,Min=4,Max=1000), WORKER: (Busy=2,Free=1021,Min=4,Max=1023), Local-CPU: n/a

Answer 1

I got same error when I set minimum TLS version to 1.2 on Azure Redis Cache, and it was caused by TLS mismatch. It was resolved by following measures.

• Add sslprotocols=tls12 to the connection string
• Add TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 to TLS cipher suites

Here is the details, Remove TLS 1.0 and 1.1 from use with Azure Cache for Redis