Bonjour,
je pense avoir trouvé la solution sur le forum kubuntu qui constate qu'il y a régulièrement des problèmes avec le preset proposé. La manip consiste à passer par DAV, j'ai fait un copier-coller plus bas et cela semble bien fonctionner.
Open KOrganizer
Setting --> Configure KOrganizer
With the General icon selected click the Calendars tab. Click Add. A window pops up where you can select the DAV groupware resource.
The DAV groupware configuration wizard window opens. Enter your email address and password and click Next.
Click cancel when the DAV groupware configuration window pops up.
The DAV groupware resource pops up. The display name is Google Calendar or whatever you want to call it. Enter your username (gmail address) and its password. Click Add.
The DAV groupware resource window pops up with CalDAV selected. Enter the remote url. Make sure "Use specific credentials" is selected and enter your gmail username (gmail address) and its password. Click Fetch. The click OK.
This is the remote url. Substitute <
youremailaddress@gmail.com> for your own gmail address.
https://www.google.com/calendar/dav/yourgmailaddress@gmail.com/events/
Click OK again. Click OK to close the Configure KOrganizer window.