Unable to load event data – in gmail when .ics sent using Java

I am sending mail with .ics file using Java. But getting this error in gmail – “Unable to load event data”

            StringBuilder sb = new StringBuilder();
            sb.append("BEGIN:VCALENDARn");
            sb.append("PRODID:-//Microsoft Corporation//Outlook 9.0 MIMEDIR//ENn");
            sb.append("VERSION:2.0n");
            sb.append("METHOD:REQUESTn");
            sb.append("BEGIN:VEVENTn");

Do I need to change

           sb.append("PRODID:-//Microsoft Corporation//Outlook 9.0 MIMEDIR//ENn");

to

           sb.append("PRODID:-//Google Inc//Google Calendar 70.9054//ENn");

But it wont work in outlook.

My question is – is there any way to we keep both ?

Answer

I found that, it was happening because organizer and recipient was same in that case.