Ics import error from exported google ics

Hi, I tried to import the calendar from exported google (ics) into https://drive.ecloud.global/apps/calendar/ but I have a warning: “contains incompatible objects”. It can only import 285/2616. Sunbird (desktop) instead (same ics), can import 2309/2616. So, I export 2309 from Sunbird to ics file, I try to import in https://drive.ecloud.global/apps/calendar/ but it only imports 307/2309 … Any idea?
Thank you

Ahh nevermind, I just added the missing entries just manually.