We tried to use tResult.%SQLCODE option also, but we got the same results. It didn't return any result.

Thank you Jeffrey for the suggestion. As you said there is a max length limit for RawContent property. I modified the code as below;

    Set pID = pReq.getId()
    
    Set tMessage = ##class(%Stream.GlobalCharacter).%New()
    Set tHL7 = ##class(EnsLib.HL7.Message).%OpenId(pID)
    Do tHL7.OutputToLibraryStream(.tMessage)

     set arrParam(1)= tMessage.Read()

Resolution/workaround  - https://community.intersystems.com/post/sql-outbound-adapter-execute-pro...