Errors in error_log

I am getting a lot of errors like this in my error_log:

[28-Sep-2015 19:12:43 UTC] WordPress database error Duplicate entry ‘ef2cc0467f853ca49fa7a62d5b1b30a0’ for key ‘PRIMARY’ for query INSERT INTO wp_livelychatsupport_convos (agent_id, token, mini_token, referrers, ip, user_agent, created_at, updated_at, last_seen) VALUES (”, ‘ef2cc0467f853ca49fa7a62d5b1b30a0’, ‘ef2’, ‘[]’, ‘174.24.45.8’, ‘Mozilla/5.0 (Windows NT 6.3; WOW64; Trident/7.0; rv:11.0) like Gecko’, ‘2015-09-28 13:12:43’, ‘2015-09-28 13:12:43’, ‘2015-09-28 13:12:43’) made by require(‘wp-blog-header.php’), require_once(‘wp-includes/template-loader.php’), include(‘/themes/organic_natural/page.php’), get_footer, locate_template, load_template, require_once(‘/themes/organic_natural/footer.php’), wp_footer, do_action(‘wp_footer’), call_user_func_array, LivelyChatSupport_frontend_footer, LivelyChatSupport_create_visitor

Can you help me stop these errors?

https://wordpress.org/plugins/lively-chat-support/