Getting 404 error when setting the Permalink structure to Post name!

Hi everybody!

Recently moved a website to WordPress and went live a few days ago. The problem now is that the Permalink structure is just the default one with numbers in it, but when trying to adjust it (via Yoast WordPress SEO) I’m getting 404 error on all pages.

I’ve seen that many people are having the same problem and I tried adding this to my htaccess file with no luck:

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

This is what the htaccess file looks like:

# BEGIN W3TC Browser Cache
<IfModule mod_deflate.c>
<IfModule mod_headers.c>
Header append Vary User-Agent env=!dont-vary
</IfModule>
AddOutputFilterByType DEFLATE text/css text/x-component application/x-javascript application/javascript text/javascript text/x-js text/html text/richtext image/svg+xml text/plain text/xsd text/xsl text/xml image/x-icon application/json
<IfModule mod_mime.c>
# DEFLATE by extension
AddOutputFilter DEFLATE js css htm html xml
</IfModule>
</IfModule>
# END W3TC Browser Cache
# BEGIN WordPress

# END WordPress

Anybody having a solution to this?? Much appreciated!