Error in the Widget section

Hi,
I’ve just installed the Corporate Plus Pro theme and the widget section does not work, I get this error:
PLEASE HELP! I’m finding it frustrating that I’ve just installed the theme and there’s already something not working.
Thank you.

Fatal error: Uncaught TypeError: array_merge(): Argument #3 must be of type array, null given in /homepages/37/d918647702/htdocs/clickandbuilds/Mesophotica/wp-includes/widgets.php:1342 Stack trace: #0 /homepages/37/d918647702/htdocs/clickandbuilds/Mesophotica/wp-includes/widgets.php(1342): array_merge(Array, Array, NULL, Array, Array, Array, Array, NULL) #1 /homepages/37/d918647702/htdocs/clickandbuilds/Mesophotica/wp-includes/rest-api/endpoints/class-wp-rest-sidebars-controller.php(298): retrieve_widgets() #2 /homepages/37/d918647702/htdocs/clickandbuilds/Mesophotica/wp-includes/rest-api/endpoints/class-wp-rest-sidebars-controller.php(97): WP_REST_Sidebars_Controller->retrieve_widgets() #3 /homepages/37/d918647702/htdocs/clickandbuilds/Mesophotica/wp-includes/rest-api/class-wp-rest-server.php(1138): WP_REST_Sidebars_Controller->get_items_permissions_check(Object(WP_REST_Request)) #4 /homepages/37/d918647702/htdocs/clickandbuilds/Mesophotica/wp-includes/rest-api/class-wp-rest-server.php(1018): WP_REST_Server->respond_to_request(Object(WP_REST_Request), ‘/wp/v2/sidebars’, Array, NULL) #5 /homepages/37/d918647702/htdocs/clickandbuilds/Mesophotica/wp-includes/rest-api.php(535): WP_REST_Server->dispatch(Object(WP_REST_Request)) #6 /homepages/37/d918647702/htdocs/clickandbuilds/Mesophotica/wp-includes/rest-api.php(2884): rest_do_request(Object(WP_REST_Request)) #7 [internal function]: rest_preload_api_request(Array, ‘/wp/v2/sidebars…’) #8 /homepages/37/d918647702/htdocs/clickandbuilds/Mesophotica/wp-includes/block-editor.php(638): array_reduce(Array, ‘rest_preload_ap…’, Array) #9 /homepages/37/d918647702/htdocs/clickandbuilds/Mesophotica/wp-admin/widgets-form-blocks.php(26): block_editor_rest_api_preload(Array, Object(WP_Block_Editor_Context)) #10 /homepages/37/d918647702/htdocs/clickandbuilds/Mesophotica/wp-admin/widgets.php(32): require(‘/homepages/37/d…’) #11 {main} thrown in /homepages/37/d918647702/htdocs/clickandbuilds/Mesophotica/wp-includes/widgets.php on line 1342