Rekordbox won't connect to iphone for synchronization

Hi there,
I'm having trouble connecting my iphone to rekordbox to synchronize the library. I can actually initiate connection but it gets stuck at 1% on the "Connecting to mobile device" box. I've waited about 30min assuming it could be related to the amount of changes in the library but it didn't do anything. It always workd fine until now.
Any idea on how to fix that?
David