Impossibile to activate Learnpress plugin

Everytime I activate the plugin this shows up and I am forced to remove it through FTP

Fatal error: Uncaught Error: Call to undefined function wp_get_current_user() in /web/htdocs/www.universitapopolare.net/home/wp-includes/capabilities.php:660 Stack trace: #0 /web/htdocs/www.universitapopolare.net/home/wp-content/plugins/learnpress/inc/admin/lp-admin-actions.php(19): current_user_can(‘manage_options’) #1 /web/htdocs/www.universitapopolare.net/home/wp-includes/class-wp-hook.php(287): _learn_press_set_user_items(Object(WP_Query)) #2 /web/htdocs/www.universitapopolare.net/home/wp-includes/class-wp-hook.php(311): WP_Hook->apply_filters(NULL, Array) #3 /web/htdocs/www.universitapopolare.net/home/wp-includes/plugin.php(544): WP_Hook->do_action(Array) #4 /web/htdocs/www.universitapopolare.net/home/wp-includes/class-wp-query.php(1768): do_action_ref_array(‘pre_get_posts’, Array) #5 /web/htdocs/www.universitapopolare.net/home/wp-includes/class-wp-query.php(3432): WP_Query->get_posts() #6 /web/htdocs/www.universitapopolare.net/home/wp-includes/post.php(2050): WP_Query->query(Array) #7 /web/htdocs/www.universitapopol in /web/htdocs/www.universitapopolare.net/home/wp-includes/capabilities.php on line 660

Site: http://www.universitapopolare.net
Theme: Eduma
Other plugins activated: All-in-One SEO Pack, Black Studio TinyMCE Widget, Cookie and Consent Solution for the GDPR & ePrivacy, Duplicate and Merge Posts, GA Google Analytics, Hummingbird, Loco Translate, MC4WP: Mailchimp for WordPress, Modern Events Calendar Lite, Ninja Forms, Page Links To, Really Simple SSL, Revolution Slider, Smush, Social Login, Social Sharing by miniOrange, The Grid, Thim Core, Thim Our Team, Thim Portfolio, Thim Testimonials, Widget Logic, WPBakery Page Builder

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