I've carefully been through all the instructions to prepare for attaching an Ubuntu Pro token to my machine running Ubuntu 18.04. Everything is updated and upgraded, Pro is running on the server, but when I run (as root)
pro attach [TOKEN]
all I get back is
Failed to attach machine. See https://ubuntu.com/pro
No explanation, nothing on ubuntu.com/pro and nothing I can find via Google.
Anyone know what I should try or where I should look, please?