Положите index.html в корень сайта на сервере. Ниже пример конфигурации Nginx.
server {
listen 80;
server_name s1gyma.ru www.s1gyma.ru;
root /var/www/s1gyma;
index index.html;
add_header X-Content-Type-Options nosniff always;
add_header X-Frame-Options SAMEORIGIN always;
add_header Referrer-Policy no-referrer-when-downgrade always;
add_header Permissions-Policy "geolocation=(), microphone=()" always;
location / {
try_files $uri $uri/ =404;
}
location ~* \.(html)$ {
expires -1;
}
location ~* \.(css|js|svg)$ {
expires 7d;
}
}