Getting This site cant be reached

Hey, so i have problem with running cloudflare on, when im doing that im getting this site cant be reached. The connection was reset, this only happen when im running cloudflare on, if i run the domain outside cloudflare its working fine. Just random when its happen so not sure if i made a weird settings on my dns settings are wrong. This doesn’t only happen to me its happening to other people to sometimes and even the sub domain where its hosted on 2 difference host and ip.