Error 500 | ERR_CONNECTION_CLOSED with Cloudflare

The Error 500 (Oops) is caused by a plugin, I’ll try to find which one
Without any plugin it’s working perfectly, after importing my list doesn’t work. Probably it doesn’t happen on my normal community because they aren’t up to date

The ERR_CONNECTION_CLOSED is releated with Cloudflare, definitely
I’ve set the “grey cloud” and it’s working now