errors that break the web

We have been forced to deactivate the plugin due to errors that have made the server fall. I copy some:
[05-Jun-2018 08:54:55 UTC] PHP Fatal error: Uncaught Error: Call to undefined function is_user_logged_in() in /home2/alupees/public_html/wp-includes/post.php:2250
Stack trace:
#0 /home2/alupees/public_html/wp-includes/post.php(6067): _count_posts_cache_key(‘telemetry’, ‘readable’)
#1 /home2/alupees/public_html/wp-includes/class-wp-hook.php(286): _transition_post_status(‘publish’, ‘new’, Object(WP_Post))
#2 /home2/alupees/public_html/wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters(”, Array)
#3 /home2/alupees/public_html/wp-includes/plugin.php(453): WP_Hook->do_action(Array)
#4 /home2/alupees/public_html/wp-includes/post.php(4095): do_action(‘transition_post…’, ‘publish’, ‘new’, Object(WP_Post))
#5 /home2/alupees/public_html/wp-includes/post.php(3555): wp_transition_post_status(‘publish’, ‘new’, Object(WP_Post))
#6 /home2/alupees/public_html/wp-content/plugins/gdpr/admin/class-gdpr-telemetry.php(151): wp_insert_post(Array)
#7 /home2/alupees/public_html/wp-content/plugins/gdpr/admin/class-gdpr-telemetry.php(130): GDPR_Telemetry->insert_post( in /home2/alupees/public_html/wp-includes/post.php on line 2250