Fatal Error on saving an event (CALDAV)

Always on saving an event calender throws a fatal error:
`[FATAL 19:30:05.205921] CalendarModel.vala:123: No calendar client was found`
but all data will sync correct with server

if you add a location (openstreetmap), calender crashes on saving event.

CalendarModel.vala:162: Kalenderobjekt kann nicht verändert werden: Unerwarteter HTTP Statuscode 415 gemeldet (Unsupported Media Type)

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