Caddy try to bind tcp port even explicitly asked to use h3 protocol only (should bind udp port only).

[ha-ku]

I tried to start caddy with servers { protocols h3 } in global settings. However, caddy seems still trying to bind to tcp port. My Caddyfile is something like this:

{
	debug
	servers {
		protocols h3
	}
	auto_https off
}

:443, www.example.site:443 {
	log {
		output stderr
	}
	tls /etc/cert/example.site/fullchain.pem /etc/cert/example.site/privkey.pem {
		protocols tls1.2
	}
	reverse_proxy * http://127.0.0.1:3000
}

Here is the caddy log output when I run sudo ./caddy run --config ./Caddyfile with something else listening on 443/tcp:

xxxx/xx/xx xx:xx:xx.xxx INFO    using provided configuration    {"config_file": "./Caddyfile", "config_adapter": ""}
xxxx/xx/xx xx:xx:xx.xxx WARN    Caddyfile input is not formatted; run the 'caddy fmt' command to fix inconsistencies    {"adapter": "caddyfile", "file": "./Caddyfile", "line": 3}
xxxx/xx/xx xx:xx:xx.xxx INFO    admin   admin endpoint started  {"address": "localhost:2019", "enforce_origin": false, "origins": ["//localhost:2019", "//[::1]:2019", "//127.0.0.1:2019"]}
xxxx/xx/xx xx:xx:xx.xxx INFO    tls.cache.maintenance   started background certificate maintenance      {"cache": "0xc000307570"}
xxxx/xx/xx xx:xx:xx.xxx DEBUG   events  event   {"name": "cached_unmanaged_cert", "id": "1f99ad13-6401-4800-b4b8-0608c329c138", "origin": "tls", "data": {"sans":["*.example.site","example.site"]}}
xxxx/xx/xx xx:xx:xx.xxx DEBUG   tls.cache       added certificate to cache      {"subjects": ["*.example.site","example.site"], "expiration": "xxxx/xx/xx xx:xx:xx.xxx", "managed": false, "issuer_key": "", "hash": "b0f70c934136bad92ab566c99cdb16fc621d325e9b57701064cfd71ff8642344", "cache_size": 1, "cache_capacity": 10000}
xxxx/xx/xx xx:xx:xx.xxx WARN    http    automatic HTTPS is completely disabled for server       {"server_name": "srv0"}
xxxx/xx/xx xx:xx:xx.xxx INFO    tls     cleaning storage unit   {"description": "FileStorage:/root/.local/share/caddy"}
xxxx/xx/xx xx:xx:xx.xxx INFO    tls.cache.maintenance   stopped background certificate maintenance      {"cache": "0xc000307570"}
Error: loading initial config: loading new config: http app module: start: listening on :443: listen tcp :443: bind: address already in use

Is there a way to make caddy really just bind to the udp port only?

By the way, I'm using caddy 2.6.2.