Error: Call to a member function getHandler() on ... /QuestionSettingsSource.php, line 25

I get the following error running drush mi quiz

[user@drupdev drupal]# drush mi quiz
PHP Fatal error:  Call to a member function getHandler() on null in /var/www/drupal/sites/all/modules/quizz_migrate/src/Source/QuestionSettingsSource.php on line 25
Drush command terminated abnormally due to an unrecoverable error. [error]
Error: Call to a member function getHandler() on null in /var/www/drupal/sites/all/modules/quizz_migrate/src/Source/QuestionSettingsSource.php, line 25

I've enabled all required quiz and quizz modules and mapped all custom fields. Not sure why I'm receiving this error. Any help appreciated!