Unable to delete data of flatpak - connection is closed error

I was using KdenLive but I messed up some of the settings so I decided to do a fresh install. When I used the GUI to remove then reinstall, the settings were intact. Then I went to the terminal and ran this command:

flatpak uninstall --delete-data org.kde.kdenlive


        ID                             Branch        Op
 1. [-] org.kde.kdenlive               stable        r
 2. [-] org.kde.kdenlive.Locale        stable        r

Uninstall complete.
Delete data for org.kde.kdenlive? [y/n]: y
error: The connection is closed

As you can see the program is deleted but when I try to remove the data it spits out a

closed

error. What can I do to fully remove all data so that I start with default settings when I reinstall it later?