SSL alert number 70 with TLSv1.3

Question

# nginx -V
nginx version: nginx/1.21.4
built with OpenSSL 1.1.1f  31 Mar 2020

I've configured nginx to support TLSv1.3.

ssl_protocols  TLSv1.2 TLSv1.3;

but i can't reach my host using TLSv1.3:

# openssl s_client -connect hostname.com:443 -tls1_3
CONNECTED(00000003)
140544753464640:error:1409442E:SSL routines:ssl3_read_bytes:tlsv1 alert protocol version:../ssl/record/rec_layer_s3.c:1543:SSL alert number 70
---
no peer certificate available
...

only TLSv1.2 works:

# openssl s_client -connect hostname.com:443 -tls1_2
CONNECTED(00000003)
...

Any host, like google.com or cloudflare.com connects fine using the same openssl command.

Of course, SSL Labs test also confirms TLSv1.3 support not enabled.

I've also read this thread and double-checked and I have one and only ssl_protocols line by cd /etc/nginx; grep -rl "ssl_protocols" which only outputs one file.