Callbacks to livepoll server require PHP allow_url_fopen = On

[MathTV]

Depending on your PHP version, you may need enable this option in php.ini:
allow_url_fopen = On

Without this option, callbacks fails with error like:

file_get_contents(https://livepoll.SERVERNAME.com:3000/startq?aid=4&qn=1&seed=5&startt=1491422448294&now=1491422768&sig=p04bufOCMruFLS3f8bFy7PjIk9M%3D): failed to open stream: no suitable wrapper could be found in /var/www/vhosts/imathas.SERVERNAME.com/assessment/showtest.php on line 2372 {error: ""}

[drlippman]

Glad you were able to figure out the issue :)