Whonix is a Kicksecure–based security hardened Linux distribution. Its main goals are to provide strong privacy and anonymity on the Internet. The operating system consists of two virtual machines, a “Workstation” and a Tor “Gateway”, running Debian GNU/Linux. All communications are forced through the Tor network.
In general you would not want to login to your own site with a VPN or Proxy. VPN/Proxy hosts/Browsers are typically used for anonymous browsing. If you have added additional custom htaccess code to your htaccess files then that custom htaccess code may be causing the 403 error. Go to the BPS Security Log page, copy your Security Log contents and either post it in your forum reply or email it to: info@ait-pro.com so I can take a look at your log contents.
.
