Resolution:
There are 4 types of message for MQ.

MQMT_REQUEST (its msgType is 1), MQMT_REPLY (its msgType is 2), MQMT_DATAGRAM (its msgType is 8) and MQMT_REPORT (its msgType is 4).

The following is the reference to these message types.
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MQMT_DATAGRAM
The message is one that does not require a reply.

MQMT_REQUEST
The message is one that requires a reply. Specify the name of the queue to which to send the reply in the ReplyToQ field. The Report field indicates how to set the MsgId and CorrelId of the reply.

MQMT_REPLY
The message is the reply to an earlier request message (MQMT_REQUEST). The message must be sent to the queue indicated by the ReplyToQ field of the request message. Use the Report field of the request to control how to set the MsgId and CorrelId of the reply.
Note:
The queue manager does not enforce the request-reply relationship. This is the responsibility of the application.

MQMT_REPORT
The message is reporting on some expected or unexpected occurrence, usually related to some other message (for example, a request message was received that contained data that was not valid). Send the message to the queue indicated by the ReplyToQ field of the message descriptor of the original message. Set the Feedback fields to indicate the nature of the report. Use the Report field of the original message to control how to set the MsgId and CorrelId of the report message. Report messages generated by the queue manager or message channel agent are always sent to the ReplyToQ queue, with the Feedback and CorrelId fields set as described above.
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If we set msgType as 1 in MQMD, and at the same time we do not specify the value of ReplyToQ field, it will throw error 2027 when the adapter tries to put the message to the MQ queue with Subscription service. You should set the ReplyToQ field at the same time.