why my nginx doesn't listen to udp 443

[hsie]

as quic doesn't work with my nginx installation, I now found out that indeed nginx doesn't listen to udp 443 at all, just wonder if someone can help me to figure out what is wrong with my configuration, so in advance!

And below is my full nginx confiugration file.

server {
listen 443 quic reuseport;
listen 443 ssl http2;
server_name www.XXXXXX.com;
root /data/www/scn;
access_log /data/logs/scnnewaccess.log;
error_log /data/logs/scnerror.log;
add_header alt-svc 'h3-23=":443"; ma=86400';

ssl_certificate /etc/letsencrypt/rsa/XXXXXX.com/fullchain.cer;
ssl_certificate_key /etc/letsencrypt/rsa/XXXXXX.com/XXXXXX.com.key;
ssl_certificate /etc/letsencrypt/ecdsa/XXXXXX.com_ecc/fullchain.cer;
ssl_certificate_key /etc/letsencrypt/ecdsa/XXXXXX.com_ecc/XXXXXX.com.key;
ssl_session_timeout 1d;
ssl_session_cache shared:SSL:50m;
ssl_session_tickets off;
ssl_dhparam dhparam.pem;
ssl_protocols TLSv1.1 TLSv1.2 TLSv1.3;                                          
ssl_ciphers TLS13+AESGCM+AES128:EECDH+AES128;
ssl_ecdh_curve X25519:P-256:P-384;
ssl_prefer_server_ciphers on; 
ssl_stapling on;
ssl_stapling_verify on;
ssl_early_data on;
proxy_set_header Early-Data $ssl_early_data;
ssl_buffer_size 4k;
pagespeed on;

pagespeed FileCachePath /data/www/ngx_pagespeed_cache;
location ~ "\.pagespeed\.([a-z]\.)?[a-z]{2}\.[^.]{10}\.[^.]+" {
  add_header "" "";
}
location ~ "^/pagespeed_static/" { }
location ~ "^/ngx_pagespeed_beacon$" { }

add_header X-Frame-Options deny;
add_header X-XSS-Protection "1; mode=block";
 
location / {
index   index.html  index.php; 
try_files $uri $uri/ @handler; 
expires 30d; 
}
...

[SoftCreatR]

Firewall?

[stevenmunro]

change add_header alt-svc 'h3-23=":443"; ma=86400'; to add_header alt-svc 'h3-29=":443"; ma=86400';