I am getting the exception MQRC_SSL_INITIALIZATION_ERROR while connecting to MQ in asp.net with c#. I am using IBM MQ Client (9.1.3) I am using amqmdnet dll (9.1.3) for the MQ connectivity. I am connecting on Windows Server 2019. 
Below are the MQ configuration details and connectivity code written: Awaiting a response at the earliest

<add key="MQ_MANAGER" value="HBAX013D"/>
   <add key="MQ_CHANNEL" value="DDS.SVR.CONN.SSL.CHL"/>
   <add key="MQ_CONNECTION" value="10.10.182.37(1514)"/>
   <add key="MQ_REPLY" value="DDS.REPLY"/>
   <add key="MQ_REQUEST" value="GEN.DISPATCHER.REQ"/>
   <add key="SSL_ALGORITHM" value="RC4_SHA_US"/>
   <add key="SSL_KEYLOCATION" value="C:\WMQClient\SSL\key12\key"/>

try
           {

               if (chkSSLEnbled.Checked == true)
               {
                   MQEnvironment.SSLCipherSpec = txtCipherSpec.Text;
                   MQEnvironment.SSLKeyRepository = txtKeyRepository.Text;
               }
              

               objMQQueueManager = new IBM.WMQ.MQQueueManager(txtMqManager.Text, txtMQChannel.Text, txtMqConnection.Text);

               objMQQueue = objMQQueueManager.AccessQueue(txtMQName.Text, MQC.MQOO_INQUIRE | MQC.MQOO_OUTPUT | MQC.MQOO_FAIL_IF_QUIESCING | MQC.MQOO_SET_IDENTITY_CONTEXT);
               //WriteLog("writeMessage: Connected to DDS MQ MAnager..", false);
              

           }
           catch (Exception ex)
           {
               txtLog.Text += "btnConnect_Click()-MQ Connectivity Process Failed with Exception: " + ex.Message
                             + Environment.NewLine + " with Inner Exception:" + ex.InnerException
                             + Environment.NewLine + " at Stack Trace: " + ex.StackTrace + Environment.NewLine;
           }
       }

Hi Alex,

Can you take a look in your client error log (%MQ_DATA_PATH%\errors\AMQERR01.LOG) and show us what it says in there about this problem? That should shed some light on the rather general MQRC_SSL_INITIALIZATION_ERROR which covers a number of possible problems.

I do wonder whether it might be the cipher spec you have chosen, RC4_SHA_US, which is probably not available on your queue manager, but the AMQERR01.LOG will say so if that is what it is. That is a very old cipher spec which has likely been deprecated/removed.

Cheers,
Morag

------------------------------
Morag Hughson
MQ Technical Education Specialist
MQGem Software Limited
Website: https://www.mqgem.com
------------------------------

The documentation Deprecated CipherSpecs lists RC4_SHA_US with notes

• These CipherSpecs are disabled when TLS 1.3 is enabled (through the AllowTLSV13 property in the qm.ini).
• These CipherSpecs are no longer supported by IBM MQ classes for Java or IBM MQ classes for JMS. For more information, see SSL/TLS CipherSpecs and CipherSuites in IBM MQ classes for Java or SSL/TLS CipherSpecs and CipherSuites in IBM MQ classes for JMS.

A nice strong one is ECDHE_RSA_AES_256_CBC_SHA384

Colin