Title: FATAL ERROR WHEN ACTIVATING PLUGIN Last modified: January 26, 2022 --- # FATAL ERROR WHEN ACTIVATING PLUGIN * Resolved [justme](https://wordpress.org/support/users/funtrick/) * (@funtrick) * [4 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-when-activating-plugin-69/) * 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](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fwordpress.org%2Fsupport%2Ftopic%2Ffatal-error-when-activating-plugin-69%2F%3Foutput_format%3Dmd&locale=en_US) to see the link]_ Viewing 7 replies - 1 through 7 (of 7 total) * [rooglez85](https://wordpress.org/support/users/rooglez85/) * (@rooglez85) * [4 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-when-activating-plugin-69/#post-15295646) * x2, and others sites in internet * [Tina](https://wordpress.org/support/users/mastertina/) * (@mastertina) * [4 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-when-activating-plugin-69/#post-15298398) * I have the same problem.. I had to deactivate the plugin until they can fix it * [davidsol](https://wordpress.org/support/users/davidsol/) * (@davidsol) * [4 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-when-activating-plugin-69/#post-15303375) * Check here, maybe it works for them while an update arrives that fixes the WP 5.9 update [https://wordpress.org/support/topic/function-not-found-3/](https://wordpress.org/support/topic/function-not-found-3/) * Thread Starter [justme](https://wordpress.org/support/users/funtrick/) * (@funtrick) * [4 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-when-activating-plugin-69/#post-15303636) * > Check here, maybe it works for them while an update arrives that fixes the > WP 5.9 update > [https://wordpress.org/support/topic/function-not-found-3/](https://wordpress.org/support/topic/function-not-found-3/) * Thanks! It worked but found this more elaborate. * You can edit the plugin /classes/Course_Settings_Tabs.php file, and change the line 17: * `$isGutenberg = apply_filters( 'use_block_editor_for_post_type', true, 'courses');` * to * `$isGutenberg = 0;` * Thread Starter [justme](https://wordpress.org/support/users/funtrick/) * (@funtrick) * [4 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-when-activating-plugin-69/#post-15303748) * The developers of Tutor LMS have also been very helpful. An update to the Plugin will be released soon. * [This new unreleased update will work and it works perfect out of the box.](https://www.dropbox.com/s/nnysiyjulasa64p/tutor-1.9.15.zip?dl=0) * The update was sent by Tutor LMS developers. * [Sergio, Professor](https://wordpress.org/support/users/sergiolemosb/) * (@sergiolemosb) * [4 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-when-activating-plugin-69/#post-15304017) * justme (@funtrick) * ``` Thank you very much! I was already getting desperate! Literally "pulling out the hair"... I downloaded and installed the Plugin, it worked perfectly. - You are fantastic! A big hug. ``` * [Tina](https://wordpress.org/support/users/mastertina/) * (@mastertina) * [4 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-when-activating-plugin-69/#post-15305111) * Hey Justme [@funtrick](https://wordpress.org/support/users/funtrick/) * Thanks a lot for sharing .. I have upload it to my website but it didn’t work and it’s giving me 404 foe my courses. I guess it’s because it needs the update of Tutor LMS Elementor Addon since I used it with all my courses.. * Any Idea about this or what to do? * Thanks again Viewing 7 replies - 1 through 7 (of 7 total) The topic ‘FATAL ERROR WHEN ACTIVATING PLUGIN’ is closed to new replies. * ![](https://ps.w.org/tutor/assets/icon-256x256.gif?rev=3193875) * [Tutor LMS - eLearning and online course solution](https://wordpress.org/plugins/tutor/) * [Frequently Asked Questions](https://wordpress.org/plugins/tutor/#faq) * [Support Threads](https://wordpress.org/support/plugin/tutor/) * [Active Topics](https://wordpress.org/support/plugin/tutor/active/) * [Unresolved Topics](https://wordpress.org/support/plugin/tutor/unresolved/) * [Reviews](https://wordpress.org/support/plugin/tutor/reviews/) ## Tags * [fatal error](https://wordpress.org/support/topic-tag/fatal-error/) * [tutor lms](https://wordpress.org/support/topic-tag/tutor-lms/) * 7 replies * 5 participants * Last reply from: [Tina](https://wordpress.org/support/users/mastertina/) * Last activity: [4 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-when-activating-plugin-69/#post-15305111) * Status: resolved