Cannot access my dashboard after loading cm pop up banner

I just uploaded cm pop up banner plugin and when clicking on the “activate” button i immediately got the following message:
Fatal error: Uncaught Error: Call to a member function get() on null in /homepages/8/d599077565/htdocs/clickandbuilds/NaiQala/wp-includes/query.php:28 Stack trace: #0 /homepages/8/d599077565/htdocs/clickandbuilds/NaiQala/wp-content/plugins/cm-pop-up-banners/backend/cm-pop-up-banners-for-wordpress-backend.php(273): get_query_var(‘post_type’) #1 /homepages/8/d599077565/htdocs/clickandbuilds/NaiQala/wp-includes/class-wp-hook.php(286): CMPopUpFlyInBackend::processQueryArg(Object(WP_Query)) #2 /homepages/8/d599077565/htdocs/clickandbuilds/NaiQala/wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters(”, Array) #3 /homepages/8/d599077565/htdocs/clickandbuilds/NaiQala/wp-includes/plugin.php(515): WP_Hook->do_action(Array) #4 /homepages/8/d599077565/htdocs/clickandbuilds/NaiQala/wp-includes/class-wp-query.php(1006): do_action_ref_array(‘parse_query’, Array) #5 /homepages/8/d599077565/htdocs/clickandbuilds/NaiQala/wp-includes/class-wp-query.php(1621): WP_Query->parse_query() #6 /homepages/8/d599077565/htdocs/clickandbuilds/Na in /homepages/8/d599077565/htdocs/clickandbuilds/NaiQala/wp-includes/query.php on line 28

Same message appears whenever I try to access my admin site from any device. I have no idea on the version of WP i’m using since I cannot access my dashboard anymore but I did an update like 3 months ago

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