Last week while uploading website files to our server via FTP, the transfer failed. Ever since then, I haven't been able to connect to the server from work.

I can connect just fine from home, or by using an FTP app on my cell phone as long as I'm on the cell network. I can't access the server from any machine on my work network. It's not a credential issue, either. The error message that I always get says that a connection cannot be established, and I am never prompted for my credentials.

I have changed absolutely nothing on our domain controller or our firewall/router.

I've contacted our ISP (who hosts the website/FTP server) and they can't find anything wrong on their end. They insist that it must be something here at the office that is blocking access.

I've also tested access to other FTP servers (ea.com, nvidia.com, etc.) so I know that port 21 is not being blocked. I'm totally stumped. Any help is much appreciated.

EDIT: wireshark info here: http://www.cloudshark.org/captures/85a118ae9296?filter=ip.dst%3D%3D66.118.64.208