if you are using Hostringer
create a .htaccess (make sure there's no file extension like .txt) in root file of ur file manager
paste the below code
RewriteEngine On
RewriteBase /
RewriteRule ^index\.html$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.html [L]
refresh the website