Go back to settings - permalinks and set your .htaccess as per follows, this being the default one:
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
Edit: reinstall your ssl, there is issues with it. Check firefox (connection not secure), double check your wp-config too and make sure everything look good.
What server are you using? Windows / linux?