FATAL ERROR WHEN ACTIVATING PLUGIN

I have been using Learndash to build my e-learning platform. Everything was cool but decided to move to TutorLMS because of some instructor specific features that come out of the box.

I started building with and customizing TutorLMS on a staging site which I have sent out to some people for beta testing. Everything was working just fine and we were billed to push to live by 31st of January only to realize now that the staging website is showing Fatal error. Here is the error.

Fatal error: Uncaught TypeError: call_user_func_array(): Argument #1 ($callback) must be a valid callback, function “_disable_block_editor_for_navigation_post_type” not found or invalid function name in /home/n8e8a65/public_html/beta/wp-includes/class-wp-hook.php:307 Stack trace: #0 /home/n8e8a65/public_html/beta/wp-includes/plugin.php(189): WP_Hook->apply_filters(true, Array) #1 /home/n8e8a65/public_html/beta/wp-content/plugins/tutor/classes/Course_Settings_Tabs.php(16): apply_filters(‘use_block_edito…’, true, ‘courses’) #2 /home/n8e8a65/public_html/beta/wp-content/plugins/tutor/classes/Tutor.php(130): TUTOR\Course_Settings_Tabs->__construct() #3 /home/n8e8a65/public_html/beta/wp-content/plugins/tutor/classes/Tutor.php(66): TUTOR\Tutor->__construct() #4 /home/n8e8a65/public_html/beta/wp-content/plugins/tutor/tutor.php(127): TUTOR\Tutor::instance() #5 /home/n8e8a65/public_html/beta/wp-content/plugins/tutor/tutor.php(132): tutor_lms() #6 /home/n8e8a65/public_html/beta/wp-settings.php(418): include_once(‘/home/n8e8a65/p…’) #7 /home/n8e8a65/public_html/beta/wp-config.php(95): require_once(‘/home/n8e8a65/p…’) #8 /home/n8e8a65/public_html/beta/wp-load.php(50): require_once(‘/home/n8e8a65/p…’) #9 /home/n8e8a65/public_html/beta/wp-admin/admin.php(34): require_once(‘/home/n8e8a65/p…’) #10 /home/n8e8a65/public_html/beta/wp-admin/plugins.php(10): require_once(‘/home/n8e8a65/p…’) #11 {main} thrown in /home/n8e8a65/public_html/beta/wp-includes/class-wp-hook.php on line 307

1. I have rolled back to the previous version. Didn’t work.
2. I have deactivated all plugins. Didn’t work.

How do I resolve this and do you think this could be a regular occurrence that can negatively affect my brand if I continue with it?

I have enabled debug mode so anyone could see the problem.

The page I need help with: [log in to see the link]