PHP outlook 2007 "not supported calendar attachment.ics" error

Question

I am using http://kigkonsult.se/iCalcreator/ for creating ics files and sending via email.

When I send this file to Outlook.com or Gmail or Outlook 2011 (Mac) I see that the file appears correctly and I can respond to the invite. I see (Accept / May be / Deny) buttons in the action bar.

Sometimes my users reported that the file doesn't appear correctly and it appears as "not supported calendar attachment.ics".

Many folks on the internet faced this problem but this is regards with "Recurring Date" syntax of the ics files. In my ICS file I don't have any recurring event definition. See below

BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//AdviseStream Inc//NONSGML kigkonsult.se iCalcreator 2.18//
CALSCALE:GREGORIAN
METHOD:REQUEST
X-WR-TIMEZONE:America/New_York
BEGIN:VEVENT
UID:20140305T153312EST-1562xbSf8a@AdviseStream Inc
DTSTAMP:20140305T203312Z
ATTENDEE;CUTYPE=INDIVIDUAL;ROLE=REQ-PARTICIPANT;PARTSTAT=ACCEPTED;RSVP=TRUE
 ;CN=John Doe:MAILTO:user1@domain1.com
ATTENDEE;CUTYPE=INDIVIDUAL;ROLE=REQ-PARTICIPANT;PARTSTAT=NEEDS-ACTION;RSVP=
 TRUE;CN=Jane Smith:MAILTO:user2@domain1.com
DESCRIPTION:
DTSTART:20140414T160000
DTEND:20140414T170000
LOCATION:John Doe's Office
ORGANIZER:MAILTO:user2@domain1.com
SEQUENCE:0
SUMMARY:Jane Smith : CL Interview : John Doe
END:VEVENT
END:VCALENDAR

I am not able to find the solution for this. Any help or pointers are appreciated.

Answer 1

This problem is now rectified.

Everyone knows that Outlook 2007 and 2010 had issue with RRULE configuration from different email clients. e.g. Lotus Notes. I was not having that problem hence, I overlooked an obvious error in my application.

Our iCal files are generated on a NFS share which is mounted on various application servers. One of the application servers used to generate the iCal file and notify email sending queue to dispatch the email with attachment.

If email worker picks up the item before the iCal file is propagated to all shared mount-points, email worker used to send a 0 byte attachment of iCal file.

Funny enough, only Outlook used to cite this as a "not supported calendar attachment.ics". Other email clients used to show email without attachment file. This was easier for me to figure out as the attachment never got delivered to the email clients.

Only Outlook confused me because of its error message.

So if you're facing this issue, please check if your attachments are going fine then investigate if you're falling in the category of RRULE.

Hope this helps.