It shows no-traffic available.
Using Jdownloader 0.9.581
using the browsers, no issue at all. I can download.

I have tried deleting the account, and re-entering the details.
Disabling API, and everything mentioned on this forum.

I also tried updating... no update was found.

I've sent you the login to try to troubleshoot. It shows 0 bytes (no traffic left), while there's still 2TB when I login using the browser.