Android Google Calendar "Unable to launch event"

Currently - and it's 27 April 2016 - the provided file opens fine on my Google Calendar for Android v.5.4-1198... But I had a similar issue and it turned out that Google Calendar failes to import .ics files that are UTF-8 with BOM. Now I send them from the server as UTF-8 without BOM and everything's fine.

I had a similar problem with .ics files created by my web application. Desktop gmail reacted to them just fine, but on android opening the attachment resulted in "Unable to launch event". ICS files generated by Google Calendar for its invitation mails worked fine, so I did some binary search and figured out the problem: my .ics files were missing the DTSTAMP property. The property is mandatory, so the mobile app was wrong to complain, I just wish the error message had been more informative.

The lesson is: the web application may be more loose than the mobile one, so don't assume you have a proper implementation of the standard just because it works fine in one or the other.

In the first case, you probably want to set the Content-Type to text/calendar

In the second case, things do work probably because you are passing in a content-disposition with a filename ending with .ics. So the client can infer the format from the extension.