More specifically, can you do the following? Open a terminal window by typing terminal in the search bar at the top of the desktop and selecting the Terminal app. From there, run the following commands and paste all the output here.
ls /etc/ostree/remotes.d
ls /etc/flatpak/remotes.d
ls /var/lib/flatpak/repo
grep -r . /etc/ostree/remotes.d /etc/flatpak/remotes.d /var/lib/flatpak/repo/config