Can not add flathub as remote of flatpak

It seems that I can’t add flathub as remote:

➜  ~ flatpak remote-add flathub https://flathub.org/repo/flathub.flatpakrepo
error: Can't load uri https://flathub.org/repo/flathub.flatpakrepo: Error resolving “127.0.01”: Name or service not known

I don’t understand the error message. Why there is a “127.0.01”? Are there any log files?