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DeleteMyMessage returns Error 20118: 'Message for given ID 1234567 does not exist' , however; when I reply to the same messageID '1234567' via AddMemberMessageRTQ and the reply went through. What is the problem?
There are two kind of message ids used in the message related APIs: one is MemberMessage.MemberMessageExchange.Question.MessageID and the other is Messages.Message.MessageID.
The MemberMessage.MemberMessageExchange.Question.MessageID represents a message for GetMemberMessage API, which is not the same as the value used for the Messages.Message.MessageID represent a message in GetMyMessages API.
When you make AddMemberMessageRTQ API call, you need to put the value of the MessageID that returned in GetMemberMessage call in AddMemberMessageRTQRequest's <ParentMessageID>50601</ParentMessageID> node.
When make DeleteMyMessages API request, the MessageID ( <MessageIDs><MessageID>MessageID </MessageID></MessageIDs> ) that you specified in the request must be retrieved from GetMyMessages API.
Sending a wrong MessageID type in the Message API calls will result in an Error 20118.