403 Forbidden Error

Hoping to get some help with this issue that has just appeared on my WordPress site, I can access the site with no problems, and I can login in to WP Admin with no problems. But then when I try and go further into any parts of the WP Admin dashboard, say Posts or Pages it gives me this error:

It appears you don't have permission to access this page.

403 Error. Forbidden.

Following google and sites with help, I tried changing the name of HT Access in the public folder which broke access to both the site and WP Admin, and then I changed the name of HT Access in the WP Admin folder, and still getting the same issue. 

If anyone has any idea on what I can do to fix this issue it would be amazing, thanks!