Codeigniter throws 502 error CloudFlare while using session

Hi, I'm using the latest version of CodeIgniter
error reproduction
Login system with Ion_auth
config sessions

$config['sess_driver'] = 'database';
$config['sess_cookie_name'] = 'ci_session';
$config['sess_expiration'] = 2592000; //30 dias
$config['sess_save_path'] = 'ci_sessions';
$config['sess_match_ip'] = FALSE;
$config['sess_time_to_update'] = $config['sess_expiration'];
$config['sess_regenerate_destroy'] = FALSE;
cloudflare / Crypto / flexible to access the site through https

start session on the web page and when I delete the sessions created directly from the table ci_sessions because they are created demaciadas is when the error 502 cloudflare occurs.
the only way i have found to fix it is to disable cloudflare redirect from https to http and wait a while and start loading the page
looking in google I find that apparently it is problem of the cookies are too large according to this article
https://stackoverflow.com/questions/31501972/codeigniter-throws-520-error-cloudflare-while-using-session
although I'm a rookie and I'm not sure. I appreciate any help.
if I delete my browser's cookies it also stops giving the error