Issues with calendar synchronization

I’m experiencing issues with calendar synchronization. When I add new events, they are not syncing. I have to manually clear the cache, but this only works with the grid view calendar, not with the list view calendar. In the latter case, even after clearing the cache, changes to the Google calendar are not reflected on the website. Until recently, I didn’t have these problems. I’ve also disabled the website cache, but it didn’t help. Is there anything else I can try to solve the problem?

The page I need help with: [log in to see the link]