Blank report displayed on certain parameter selections.

I have a crystal report that generates data for any day based on date selection. However for certain date selections the report is blank even if data is present. When I debug the application the report displays correctly for that date but doesn't display when its hosted on the server.

For example it has been displaying data properly till 15-06-2015, but thereafter till 21-06-2015, nothing is displayed and again displays the report properly from 22-06-2015. This report displays just the table shell without any data, if no data is present, but in this case an empty page is displayed.

I have a strongly typed dataset 'customreport'

Dim myds As New customreport
myds.EnforceConstraints = False
Dim rpt As New ReportDocument
rpt.Load(Server.MapPath("receiptregister.rpt"))

da.Fill(myds, "customreport1")
rpt.SetDataSource(myds)
rpt.SetParameterValue(0, dtparam)
rpt.SetParameterValue(1, Session("OfficeName"))
CrystalReportViewer1.ReportSource = rpt
CrystalReportViewer1.DataBind()
Dim oStream As MemoryStream
oStream = CType(rpt.ExportToStream(ExportFormatType.PortableDocFormat), MemoryStream)
Response.Clear()
Response.Buffer = True
Response.ContentType = "application/pdf"
Response.BinaryWrite(oStream.ToArray())            

Here is a screenshot for references http://prntscr.com/7ju965

I'm at my wits end. Please help!