If edits you made on the web won't sync to your iPad:
First, make sure you're running the most recent version of Haiku Deck. If you are, or if updating doesn't help, try tapping the Main Menu button in the top left corner of the app, then returning to edit your deck. If it's still not working, verify you have a functional internet connection on your iPad, and that you're not blocked by any firewalls or security systems on that network. If you're still stuck, follow these steps.
If edits you made on the iPad aren't showing up on the web:
Make sure you're signed into the right account, that you have a functional network connection on your iPad, and that you have the latest update for Haiku Deck available in the App Store. It might also help to try closing and reopening your browser on the web.