Troubleshooting: Unable to Log in to PHP-Nuke Site
PHP-Nuke Login Not Working Explanation
When transferring an existing set of nameservers and the website uses a CMS (Content Management System) based on PHP-Nuke, you may have to wait until the NS is fully propagated before you can access the websites with a username and password. This is due to the cookie validation process that the CMS systems use. When using the interim web address (for example, http://box###.bluehost/~username), the CMS will attempt to assign cookies for the website you have assigned in the system (most likely www.mywebsite.com).