Nginx Configuration Problem

I made Nginx configuration. I got error message after this command: sudo nginx -t && sudo systemctl reload nginx Error Message:

nginx: [emerg] "server_tokens" directive is duplicate in /etc/nginx/conf.d/dokku.conf:3
nginx: configuration file /etc/nginx/nginx.conf test failed

dokku.conf:

server_tokens off;

# Settings from https://mozilla.github.io/server-side-tls/ssl-config-generator/
ssl_session_cache   shared:SSL:20m;
ssl_session_timeout 1d;
ssl_session_tickets off;

ssl_dhparam /etc/nginx/dhparam.pem;
ssl_ciphers ECDHE-ECDSA-AE.......

nginx.conf:

# Generated by nginxconfig.io
# https://www.digitalocean.com/community/tools/nginx?domains.0.server.domain=vo$

user                 www-data;
pid                  /run/nginx.pid;
worker_processes     auto;
worker_rlimit_nofile 65535;

events {
    multi_accept       on;
    worker_connections 65535;
}

http {
    charset              utf-8;
    sendfile             on;
    tcp_nopush           on;
    tcp_nodelay          on;
    server_tokens        off;
     log_not_found        off;
    types_hash_max_size  2048;
    client_max_body_size 16M;

    # MIME
    include              mime.types;
    default_type         application/octet-stream;

    # Logging
    access_log           /var/log/nginx/access.log;
    error_log            /var/log/nginx/error.log warn;

    # SSL
    ssl_session_timeout  1d;
    ssl_session_cache    shared:SSL:10m;
    ssl_session_tickets  off;

    # Diffie-Hellman parameter for DHE ciphersuites
    ssl_dhparam          /etc/nginx/dhparam.pem;
     ssl_protocols        TLSv1.2 TLSv1.3;
    ssl_ciphers          ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA$

    # OCSP Stapling
    ssl_stapling         on;
    ssl_stapling_verify  on;
    resolver             1.1.1.1 1.0.0.1 8.8.8.8 8.8.4.4 208.67.222.222 208.67.$
    resolver_timeout     2s;

    # Load configs
    include              /etc/nginx/conf.d/*.conf;
    include              /etc/nginx/sites-enabled/*;
}

How can I fix this problem? Thanks.