Request to Github page returns "curl: (35) error:1404B42E:SSL routines:ST_CONNECT:tlsv1 alert protocol version"

I'm trying to open pola-rs' documentation but my browser returns an SSL error

This site can’t provide a secure connection
pola-rs.github.io sent an invalid response.
ERR_SSL_PROTOCOL_ERROR

So I tried downloading with curl, which gives the following error:

$ curl https://pola-rs.github.io/polars-book/ --verbose  
*   Trying 185.199.111.153:443...
* Connected to pola-rs.github.io (185.199.111.153) port 443 (#0)
* ALPN: offers h2
* ALPN: offers http/1.1
*  CAfile: /etc/ssl/cert.pem
*  CApath: none
* (304) (OUT), TLS handshake, Client hello (1):
* error:1404B42E:SSL routines:ST_CONNECT:tlsv1 alert protocol version
* Closing connection 0
curl: (35) error:1404B42E:SSL routines:ST_CONNECT:tlsv1 alert protocol version

Is the problem on the Github page deployment side or am I doing something wrong?

Using a different version of OpenSSL (from conda-forge) I get a similar but different error message:

$ curl https://pola-rs.github.io/polars-book/ --verbose
*   Trying 185.199.111.153:443...
* Connected to pola-rs.github.io (185.199.111.153) port 443 (#0)
* ALPN: offers h2
* ALPN: offers http/1.1
*  CAfile: /opt/homebrew/Caskroom/miniforge/base/envs/nextstrain/ssl/cacert.pem
*  CApath: none
* [CONN-0-0][CF-SSL] TLSv1.3 (OUT), TLS handshake, Client hello (1):
* OpenSSL/1.1.1t: error:1408F10B:SSL routines:ssl3_get_record:wrong version number
* Closing connection 0
curl: (35) OpenSSL/1.1.1t: error:1408F10B:SSL routines:ssl3_get_record:wrong version number

Solution

In this case, the reason was that I had my ASUS router's (dumb) "AiProtection" turned on and it blocked the polars website as "malicious".

Turning off "AiProtection" fixed it.

One can try to get false positives removed via https://global.sitesafety.trendmicro.com