Time Capsule Connection Failed after update to Mavericks
In my case a serie of rabid and chaotic experiments with restarts and erasing a plist fixed the issue. Steps I did were: 


Disabled TM Backup
Removed TimeCapsule from TM Backup Disk (this might not be necessary, you will not be able to add it again until it will start to work)
Saving a screenshot of Exluded paths in TM Options (just for the case)
Renamed /Library/Preferences/com.apple.TimeMachine.plist to *.bac
Restarted Mac
Restarted TimeMachine
Removed /Library/Preferences/com.apple.TimeMachine.plist and renamed the old plist back
Restarted Mac again
Added a TimeCapsule back to TimeMachine Backup Disks


Hopefully it started to work. I don't know which of the steps were necessary and which just desperate.