Error When Add Flathub Repo To Flatpak In Ubuntu 21.04

When I Try To Add Flathub Repo I Found This Error Code :

localhost% flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
error: Creating repo: linkat: Operation not permitted
localhost%

What Should I Do?

Do you receive same error if you use sudo?