When I try and setup the sync with dropbox on my iPhone 6Plus, I select Sync existing vault > Sync with Dropbox > Select Account XXXXXX > Choose Vault /1Password.agilekeychain and get a screen which says Cancel and Dropbox, but is otherwise entirely blank (other than a grey background at the top of the screen). In the background it opens up Dropbox. Sometimes when I am changing application I briefly see a screen where it seems to be saying it is syncing, but the screen always disappears very quickly.
I have tried the following:
The dropbox sync still works on Windows 8.1 PC and presumably on my other devices.