Whenever avast is not blocking through the shields getting to a site or WOT or Google Safebrowsing or Bitdefender TrafficLight block a site,
a site could also be offline for other reasons and temporarily not available.
You could check with web bug tool, see: http://www.cyberspyder.com/webbug.html (allow as avast pop may detect this program when first launched)
See attached image, but you could also check online…
Check for instance like this: http://doj.me/?url=ask.com
Or use: http://www.downforeveryoneorjustme.com/ask.com
or: http://www.isitdownrightnow.com/
You can also use: http://www.checksite.us/
Or Netirk: http://www.netirk.com/
Nice knowledge base: http://whirlpool.net.au/wiki/is_this_site_down (authors pixelkitty and manfred)
What service do you use by the way?
polonus