File and Folder Permissions
Your file and folder permissions if set wrongly, it can also cause a HTTP 403 error. Try setting folders to 755 and files to 644.
- Login to your web server using FTP.
- Go to the file and right click. Choose Permissions or Attributes or Properties (depends on your program).
- You should be able to see it's permission.
.htaccess
Check your .htaccess file for any codes that are not added by WordPress. Your plugin could have added them and it could have been incompatible with your setup and blocked your access. A basic WordPress .htaccess looks something as follows.
# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPress
บทความจาก http://docs.presscustomizr.com/article/195-http-error-403
