Forbidden error on all admin links

Hi all,
I am a huge novice at WP – so please bear with me with terminology and wordings!
We have an issue where by our website works however when we log into the WP admin panel (which we can do) we hit a error message:
Forbidden
You don’t have permission to access /wp-admin/edit.php on this server.
This happens on every link that we have on the admin panel.

I have tried to use FileZilla to look at the file and folder numbers as well as the .htaccess file etc – but none of these elements have cured the issue.

I was wondering what else i can try?

Thanks
Iain