Flatpak problem on fedora 38 xfce

I tried to install web (epipjany browser) with the following command,
but a problem occurred…

flatpak install flathub org.gnome.Epiphany
Looking for matches…
error: No remote refs found for ‘flathub’

[although flatpak has already been installed]

Please check what flatpak remotes shows.

If flathub is not listed try:

flatpak remote-add https://flathub.org/

flatpak is the command (and also the name of the packaging format and technology)

Flathub is a repository for Flatpak packages.

“Remote” in Flatpak terminology means remote repository.

To add the Flathub remote:

flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo

problem solved!