Why can't I suddenly open certain website - innocent ones like Argos or Myvouchercodes? Neither of them known for their dodgy content!

[MyCatIsABiggerBastardThanYours]

I am linked to the internet. All is running fine, but I keep being told that I cannot access Argos. It isn't the website (I think) as I also can't access Myvouchercodes.

Not normally a problem but a tad annoying when trying to do my Christmas shopping.

I use Comodo internet security (if that helps anyone).

Is my security blocking them for some reason?

Ignore me, I'm a twat. Working now.