I was having the same problem with SwissDisk, so I set up a free account at MyDisk.se and it works just fine.
Here's what to do:
1. Set up the free account at
www.mydisk.se (you'll choose a username and password)
2. In the OF desktop client, go to the sync preferences and replace the swissdisk URL with this:
https://mydisk.se/username
3. Click "Sync Now" (you'll need to enter your new username and password when prompted)
4. Then do the same on your iPhone or other clients.
Bingo, everything should be working as it was before, except you're using mydisk.se (which offers 2GB free storage).