Too many requests error 429

Hello OneCalendar Team,

we currently have an issue when synchronizing our calendar with M365. We get a too many requests error 429 from one calendar. We can just dismiss this error and the calendar keeps working fine, but it is showing again and again.
We tried to fix this issue by removing all calendar entries from the past year so there are not too many synchronized. This unfortunately did not help.
Is there any solution to this issue?