Hi Martin,
Thanks so much for reaching out!
It is possible that your calendar is no longer syncing because the feed can only hold 30 data items (or events in this case) at this time.
That said, there is a way to link to the feed in Google Calendar in such a way that it contains event data for the entire year, which is noted in this thread:
https://theeventscalendar.com/support/forums/topic/ical-import-only-gets-30-events/
If that doesn’t help, would you please provide me with the URL that you use to sync your calendar?
Let me know how it goes!
Thanks,
Jaime