Email Settings & Template: PHP Fatal Error (php v. 7.0)

Hi,
when I try to access to the “Email Settings & Template” on a Ubuntu18 w/php 7.0 the page loading stops, and I get this error:

[06-Oct-2020 15:06:40 UTC] PHP Fatal error:  Uncaught TypeError: Return value of WP2FA\EmailTemplate::setCanBeToggled() must be an instance of WP2FA\void, none returned in /path/to/wp/wp-content/plugins/wp-2fa/includes/classes/EmailTemplate.php:58
Stack trace:
#0 /path/to/wp/wp-content/plugins/wp-2fa/includes/classes/Admin/SettingsPage.php(1559): WP2FA\EmailTemplate->setCanBeToggled(false)
#1 /path/to/wp/wp-content/plugins/wp-2fa/includes/classes/Admin/SettingsPage.php(1569): WP2FA\Admin\SettingsPage->get_email_notification_definitions()
#2 /path/to/wp/wp-content/plugins/wp-2fa/includes/classes/Admin/SettingsPage.php(219): WP2FA\Admin\SettingsPage->email_settings()
#3 /path/to/wp/wp-includes/class-wp-hook.php(287): WP2FA\Admin\SettingsPage->settings_page_render('')
#4 /path/to/wp/wp-includes/class-wp-hook.php(311): WP_Hook->apply_filters('', Array)
#5 /path/to/wp/wp-includes/plugin.php(478): WP_Hook->do_action(Array in /path/to/wp/wp-content/plugins/wp-2fa/includes/classes/EmailTemplate.php on line 58

But if I run the same wp installation in a Ubuntu 18 w/php 7.3 everything works fine.

Thank You

G