That's a surprisingly honest error message.
I'm on PC EU and I was just standing in Alinor previewing motifs I'd just unlocked in the Collection's menu when the game froze, then booted me to the login screen and gave me that message. That was about 5 minutes ago and every time I try to log in I get the same message. Until this happened I'd been online for a few hours (doing master writs and buying motifs) and hadn't had any noticable lag or other problems.
I'm not sure anything can be done about it, but I thought I should report it just in case.
Edit: A few minutes after posting this I was eventually able to log in again.
Edited by Danikat on December 14, 2019 9:11PM PC EU player | She/her/hers | PAWS (Positively Against Wrip-off Stuff) - Say No to Crown Crates!
"Remember in this game we call life that no one said it's fair"