I have had an authenticator connected since… forever.
- Click login on the forums
- Get redirected to https://account.arena.net/login/wait/totp with all the OAuth2 parameters
- Enter E-Mail (shake head at “Did you mean ….net?”) and password
- Submit
- Enter authenticator code (ignoring remember network)
- Submit
at this point nothing happens (visually). In the background stuff is submitted and a json response received. At this point further submits yield a “Some fields are invalid; please fix them.” at the top and another background request resulting in a HTTP 400 error.
Going back to the forums will still show you logged out, but clicking Login again passes you back and forth and results with you logged in.