I was wondering if anybody knows how to fix this problem. The page was working fine yesterday night, but now it keeps displaying this message. I searched the progress error log and it says to contact Progress. I'm not too sure what I can do. Can anybody help?
If absolutely nothing has changed in your environment or code, then you need to restart the wtb broker at least and possibly the nameserver if you're using it.
This error is telling you that the progress agent that runs on your behalf to service http requests is not returning a valid html page. This can be because of any number of reasons and we would need more info in order to help you find the cause.
What version of progress/webspeed, what os are you running on, have you looked at the wtb server and broker logs?