@Tiberius1976 It seems that you’re affected by the problems with the version from Amazon, too. Others have this problem as well. Have a look here: https://forums.bitfire.at/topic/766/amazon-store-ical4j-exception-when-syncing-calendars
Amazon has now found a solution and fixed the problem. 🙂
Everything is working again and 1.0.5 is available in Amazon Store!