FTP access failing to macosx.com account


I was able to use Transmit to upload files to my httpdocs directory for a little while. Then suddenly it stopped working. Get this error msg:
"Could not connect to server 'ftp.projectsphinx.com'. Server closed connection."
What does that mean? Why is FTP no longer working? Is it a system wide issue, or something particular to my domain-- some setting perhaps?
I've tried relaunching Transmit, checking logins/passwords via Plesk, rebooting. Since FTP was working briefly and I did not change any settings in Plesk I'm not sure what to do.
The Plesk File Manager is allowing me to upload files (which I assume uses FTP behind the scenes). But unfortunately I have many pages to upload and the Plesk one-file-at-a-time approach is way too slow.
I hope someone can help me. I really like macosx.com so far. Thanks in advance for any insights.
There has been a behind the scenes upgrade that probably needs a bit of tweaking.
Did you submit a contact form from the services link? If so, give it some time to be resolved. You will hear from Scott.
FTP is working again! THANKS to all who were involved in the behind the scenes fix. I'm very new to macosx.com, and I'm learning to manage my own domain here. So I appreciate your efforts. In fact, once I learn enough I'll fill out an application to volunteer in the free support area. This is a happening mac community! Thanks again.