Relays running on CloudFare, check your Tor config. 

nostr:npub16r0tl8a39hhcrapa03559xahsjqj4s0y6t2n5gpdk64v06jtgekqdkz5pl did a few tests and it looks like CF is blocking everything that is not a Tor Browser by default. It is common to see the relay operational through a known Tor agent while at the same time sending 403s when clients try to connect.