iphone 6s calendar doesn't synchronize with outlook 2007 calendar

Since a couple of days my outlook 2007 calendar doesn't show icloud updates anymore. Tried many things to get icloud back into Outlook but no success. Before there were pop ups saying that extreme errors occured. The icloud entry in outlook couldn't be opened anymore as it was declared to be corrup i.e. not working properly anymore. So I removed it and thought by deactivating and reactivating "Contacts, Calendar, Tasks" I would able to restore a properly working iCloud entry in Outlook 2007. But with no success whatsoever.