I have always failed syncing calendar appointments from outlook to my 8520 device. This probem occurs since several days ago, all of a sudden...

I have no problem syncing my outlook appointments with my other devices (iPhone and O2), but everytime I try to sync it with my 8520, no appointments added to the device, except for the ones already synced before

Need help, any suggestions will do me a great favor.
Thanks, everyone!