help me to fix .htaccess

Hi,

I transfered my wp blog to one host to another one, migrated everything
from database to files, but site is refusing to open. showing 500 error.
i read here about it
https://codex.www.ads-software.com/Using_Permalinks#Creating_and_editing_.28.htaccess.29
that it is a .htaccess file error but can’t figure it down.
content of my .htaccess file is

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /howto/index.php [L]
</IfModule>
# END WordPress

and the url is https://www.gangoos.com/howto

take a look.
Thanks.