I as well was having this very same problem... same cam, same router, same ISP. Just tried changing the DNS settings like the user above just mentions. Have to get to my office to see if the camera is working now over the net.
One thing I would like to add that I figured out or stumbled upon... when I was trying to figure out why this wasn't working anymore... I played with the connection types. I noticed that if I left it on UDP or TCP I could not see my camera from where I have it embedded on my website however if I changed the type to HTTP I could at least see it there locally - meaning viewing the page from a computer connected to my network. Thinking I had solved the issue (at least without audio) I waited until the next day to test it from the office. No luck. Hopefully this DNS thing works.
