I'M EXPERIENCING THE SAME:
I have an Helix stomp 2.82 and want to update to 2.92 firmware.
After a log in (successful) via web site and downloading hx edit 2.90 I proceed to the firmware update via software (hx edit 2.90 indeed on a macbook with MAC OS 10.11.6) but it ask me username and psw and stop: can't connect with my account! No connection, no update.
How can I fix this problem?