Cludflare ssl/tls nginx "ERR_SSL_VERSION_OR_CIPHER_MISMATCH" Error

Question

I'm encountering an SSL issue while trying to use Cloudflare. Despite successfully configuring SSL for another site, I'm now facing either an "ERR_SSL_VERSION_OR_CIPHER_MISMATCH" or "No required SSL certificate" error. Below is my Nginx configuration:

server {
    listen 80 default_server;
    listen [::]:80 default_server;

    server_name www.domain.com domain.com;
    return 302 https://$server_name$request_uri;
}

server {
    server_name www.domain.com domain.com;
    listen 443 ssl http2;
    listen [::]:443 ssl http2;
    ssl_certificate         /etc/ssl/cert.pem;
    ssl_certificate_key     /etc/ssl/key.pem;
    ssl_client_certificate /etc/ssl/cloudflare.crt;
    ssl_verify_client on;

    location = /favicon.ico { access_log off; log_not_found off; }
    location /static/ {
        root /home/hesamz3090/domain;
    }
    location /media/ {
        root /home/hesamz3090/domain;
    }

    location / {
        include proxy_params;
        proxy_pass http://unix:/run/domain.sock;
    }

}

I've followed this tutorial to enable SSL with Cloudflare, and my SSL mode is set to "Full (strict)" with Universal SSL/TLS and Authenticated Origin Pulls activated.

However, when I check DNS proxy, it shows the error "This hostname is not covered by a certificate." Can you help me troubleshoot this issue?

Disabling the DNS proxy resulted in a "No required SSL certificate was sent" error. I attempted commenting out the lines:

ssl_client_certificate /etc/ssl/cloudflare.crt
ssl_verify_client on;   

However, the issue persisted. As a workaround, I changed the SSL mode to "Full." This allowed the site to load, but it's marked as "Not Secure" with a warning on the page due to the SSL certificate not being fully recognized.