Akonadi issue with HTTPS ical file

Hello,

I'm unable to import remote ical files from my own site into Kontact, ex:
https://www.flexygames.net/player/cal/73215?token=00411d5e-e41d-43ae-8350-26fd403a5f7d

In the import wizard I just select "ical file" and I set "read only" and no
monitoring, is it correct ?

On my last tries, nothing happens: updates do nothing and I can see there's
0 entry in the Akonadi console. But on my previous tries, I had some
crashes or some logs like "org.kde.pim.akonadiserver: ItemRetrievalJob for
request 31154 finished" displayed infinitely every fews seconds.

Thanks for your help, Vincent.

PS: I know my ical files are not perfect, there are some RFC violations
related to timezones, but that shouldn't prevent Akonadi to import them (it
works fine with Nextcloud, Outlook...).