Database error and 402 error

Hello,

I installed learnpress on my website. But I got the error 402 when enrolling to a course. I tried to upgrade the database in the settings but it gives me the error “Step clone_tables: Table ‘na9xv_WP723721.wp_723721_learnpress_user_items_bk’ doesn’t exist”. I then tried to delete the tables of learnpress in the database and reinstall the plugin. It still doesn’t work and now it only creates 2 tables “wp_723721_learnpress_upgrade_db” and “wp_723721_learnpress_user_item_results”.
How can I fix this ?

Thank you.