page not found in angular in gcp server code example

Example: Not Found The requested URL was not found on this server angular routing when going back to site from ecternal source

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.html$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.html [L]
</IfModule>