I've confirmed that the user and password I'm trying to log in with are in the output from autoconfig-users-freepbx.sh. My session times out when I try to log in.
I've double-checked that the response from file /tmp/buttons.cfg returns ASCII text.
I suspected a bad character in the licensee name (I used an apostrophe), and tried to revoke the license, change the name and re-register, but perhaps I can't change the licensee name on my own after registering.
I will email you my registration code.