Premier Business Direct Website Sign in Issue

Please provide me with technical t-shooting information to troubleshoot the following situation:

1. From home, I can access the

https://www.wireless.att.com/businesscare

site with no problems.  I can sign in using my credentials and have access to my account.

2. When I attempt to sign in from work, I get the following error message:

Your company's Premier site is currently undergoing maintenance. Contact your company administrator to place your order.

We have troubleshooted this down and removed all firewalls, updated our java, used the appropriate browser, and tested on multiple clients.... all fail.  Furthermore, when I have VPN'd to our office from home, suddenly I can no longer access it from my home client.  So a client that was perfectly capable of accessing the site was now blocked, because the traffic to the AT&T site originates from a specific IP address (remember, no firewall or other issues that would impede the traffic).

Since we want to use this service from work, please provide us with the appropriate technical resources from AT&T to resolve this issue.

Access to this site from work has never worked over the past 20+ months.

Like in all other threads indicating this same problem, please email me at the address associated with this forum account.

Thank you.