Crash on Installation

Immediately after installing Ultimate Member (but before activating it), my dashboard and site crash. The error message it gives me is below. Stats: I’m using the latest version of InstantWP, with WordPress 5.3 and PHP 7.1, and I’ve tried uninstalling all other plugins. Any ideas?

Fatal error: Uncaught Error: Call to undefined function um\core\token_get_all() in /var/www/localhost/htdocs/wordpress/wp-content/plugins/ultimate-member/includes/core/class-shortcodes.php:912 Stack trace: #0 /var/www/localhost/htdocs/wordpress/wp-content/plugins/ultimate-member/includes/admin/core/class-admin-settings.php(707): um\core\Shortcodes->get_templates(‘profile’) #1 /var/www/localhost/htdocs/wordpress/wp-includes/class-wp-hook.php(288): um\admin\core\Admin_Settings->init_variables(”) #2 /var/www/localhost/htdocs/wordpress/wp-includes/class-wp-hook.php(312): WP_Hook->apply_filters(NULL, Array) #3 /var/www/localhost/htdocs/wordpress/wp-includes/plugin.php(478): WP_Hook->do_action(Array) #4 /var/www/localhost/htdocs/wordpress/wp-admin/admin.php(170): do_action(‘admin_init’) #5 /var/www/localhost/htdocs/wordpress/wp-admin/plugins.php(10): require_once(‘/var/www/localh…’) #6 {main} thrown in /var/www/localhost/htdocs/wordpress/wp-content/plugins/ultimate-member/includes/core/class-shortcodes.php on line 912