Getting 400 BAD Request ERR 904 on Ubuntu 18

Your realm as sent to privacyidea is “raysono.int\t”.
Are you sure you called your realm in privacyIDEA with a “tab” at the end.

You need to check your radius client, your radius server config - did you configure a default realm?
Guys, you should really provide more information.
And honestly, when gathering this information you will probably find the explanation to the problem yourself.