KyBook 3“BAD GATEWAY “ reply:Impossible to register my KyBook3

I have never been able to register my account with KYBOOK3 app and therefore cannot synchronise my KYBOOK 3 account, i.e. use it on more than this one device.  Whatever I try, KYBOOK 3 responds with “BAD GATEWAY “ and nothing more.  Please help. My email address is:jodisl@icloud.com.  Thanks in advance for your help.