Hi oldman 50, I'm afraid there are lots of possible reasons that you may be getting this error so there's no easy answer! Some of these are: Your ISP (Internet Service Provider) may be blocking certain ports preventing access, the website may be offline or having difficulties, your PC may have a Virus or Spyware, there may be too much internet traffic to or from this website, the IP settings on your PC or Router could be conficting. Or worst of all......, you may have no internet access at all! (you should be able to tell if this is the case though)
Hope this is of some help