title: Microsoft.DataTransfer.Common.Shared.HybridDeliveryException TypeName cannot be null
body: <p>I have a data factory that copies data from a restful webservice into an Azure Data Warehouse. I have tested and previewed all connections and datasets.<br>
  I'm receiving the following error message.</p>
  
  <pre><code>{
      "errorCode": "2200",  
      "message":   "ErrorCode=InvalidParameter,'Type=Microsoft.DataTransfer.Common.Shared.HybridDeliveryException,Message=The value of the property &amp;apos;typeName&amp;apos; is invalid: &amp;apos;Value cannot be null.\r\nParameter name: typeName&amp;apos;.,Source=,''Type=System.ArgumentNullException,Message=Value cannot be null.\r\nParameter name: typeName,Source=Microsoft.DataTransfer.Common,'",
      "failureType": "UserError",  
      "target": "ImportLegs"  
  }
  </code></pre>
  
  <p>Pipeline source</p>
  
  <pre><code>{
      "name": "Import Trip Data",
      "properties": {
          "activities": [
              {
                  "name": "ImportLegs",
                  "type": "Copy",
                  "policy": {
                      "timeout": "7.00:00:00",
                      "retry": 0,
                      "retryIntervalInSeconds": 30,
                      "secureOutput": false,
                      "secureInput": false
                  },
                  "userProperties": [
                      {
                          "name": "Source",
                          "value": "flightleg?StartDate=01/01/2018&amp;EndDate=02/01/2018"
                      },
                      {
                          "name": "Destination",
                          "value": "[Trip].[Leg]"
                      }
                  ],
                  "typeProperties": {
                      "source": {
                          "type": "RestSource",
                          "httpRequestTimeout": "00:01:40",
                          "requestInterval": "00.00:00:00.010"
                      },
                      "sink": {
                          "type": "SqlDWSink",
                          "allowPolyBase": false,
                          "writeBatchSize": 10000
                      },
                      "enableStaging": false,
                      "enableSkipIncompatibleRow": true,
                      "translator": {
                          "type": "TabularTranslator",
                          "mappings": [
                              {
                                  "source": {
                                      "path": "id"
                                  },
                                  "sink": {
                                      "name": "Origin"
                                  }
                              },
                              {
                                  "source": {
                                      "path": "actualArrivalDateLocal"
                                  },
                                  "sink": {
                                      "name": "Destination"
                                  }
                              },
                              {
                                  "source": {
                                      "path": "actualArrivalDateUTC"
                                  },
                                  "sink": {
                                      "name": "FlightLogDistance"
                                  }
                              },
                              {
                                  "source": {
                                      "path": "actualBlockTime"
                                  },
                                  "sink": {
                                      "name": "FlightLogFlightTime"
                                  }
                              },
                              {
                                  "source": {
                                      "path": "actualDepartureDateLocal"
                                  },
                                  "sink": {
                                      "name": "Aircraft"
                                  }
                              },
                              {
                                  "source": {
                                      "path": "actualDepartureDateUTC"
                                  },
                                  "sink": {
                                      "name": "ScheduledDepartDate"
                                  }
                              }
                          ]
                      }
                  },
                  "inputs": [
                      {
                          "referenceName": "FlightLeg",
                          "type": "DatasetReference"
                      }
                  ],
                  "outputs": [
                      {
                          "referenceName": "TripLegDW",
                          "type": "DatasetReference"
                      }
                  ]
              }
          ]
      },
      "type": "Microsoft.DataFactory/factories/pipelines"
  }
  </code></pre>