The appcenter flatpak remote was replaced with another one by mistake.

[zhchmmx]

I was trying to install apps from flatpak in elementary os in China when I found I can't connect to the server. So I tried many ways to solve this problem, including change the url of appcenter remote into flatpak's one. But now the appcenter's remote can't work properly. Can anyone tell me how to restore the appcenter remote? Thanks.