Graph Control does not display Blood Pressure data

Though the blood pressure data is present and visible in Flow Sheet Control it is not getting displayed on the graph control but it displays the measuring unit on Y-axis correctly as shown in this image and the related config

       "VitalsGraph": {
         "type": "observationGraph",
         "title": "Vitals Graph",
         "config": {
            "yAxisConcepts": ["Systolic", "Diastolic"],
            "xAxisConcept" : "observationDateTime",
            "numberOfVisits": 4