Getting ERR_CERT_AUTHORITY_INVALID error

Hi, I created droplet in Digital Ocean where I am running my nodejs application. I bought a domain in Namecheap and point it to my ip adress of a droplet. I also installed let’s encrypt ssl for that domain in my droplet. When I access to my domain I am getting an error: ‘An application is stopping Chrome from safely connecting to this site’ (NET:ERR_CERT_AUTHORITY_INVALID). I am attaching my nginx default config below Do you know if this is because I am using the free let’s encrypt ssl or there is something wrong in my settings?

server {

    server_name domain www.domain;

    location / {

proxy_pass http://localhost:3000;

    }


    listen 443 ssl; # managed by Certbot

    ssl_certificate /etc/letsencrypt/live/domain/fullchain.pem; # managed by Certbot

    ssl_certificate_key /etc/letsencrypt/live/domain/privkey.pem; # managed by Certbot

    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot

    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot

}

server {

    if ($host = www.domain) {

        return 301 https://$host$request_uri;

    } # managed by Certbot


    if ($host = domain) {

        return 301 https://$host$request_uri;

    } # managed by Certbot


    listen 80;

    server_name domain www.domain;

    return 404; # managed by Certbot
}