Cannot enter any secure sites - SSL error

Hello.

New member here, and a big fan of Comodo Dragon.

But… i have a problem: I cannot enter any SSL sites in Comodo, such as this one or any other https ones. It all started with some sites only, a few weeks ago, but it got worse since yesterday and now i can’t access any single one (SSL error)… I only have this problem with Comodo. Not in Firefox or even Chrome. My anti virus is Avast.

Thanks in advance for your help.