[CalendarServer-users] Limitations on number events?

Hello, are there limitations on the amount of events each user can have? I have several users with 1000+ events that seems to cause the server to fail, returning null: iCal[5423]: CalDAV CalDAVCalendarRefreshOperation failed: status 'HTTP/1.1 207 Multi-Status' request:\n <?xml version="1.0" encoding="utf-8"?> <x0:propfind xmlns:x0="DAV:"> <x0:prop> <x0:getetag/> <x0:resourcetype/> </x0:prop> </x0:propfind> ... response: (null)