Why can't I access 'ssl' encrypted sites?

I cannot access the signup page on www.clickbank.com when i try to sign up, IE6 says "page cannot be displayed". So do opera & mozilla.
Do you know why this is?

I've tried lowering the security settings on my brousers, and checked my router & firewall/anitvir. The only thing i did was update my Linksys Router Firmware. But i'm not sure that's the reason as i updated it along time ago and im 70% sure i used ccbill.com after that, but now ccbill.com wont work and niether will clickbank.com.

Can you access any other SSL/HTTPS sites? If not can you do so with another computer on the same internet link? Can you roll back to the previous firmware? 30% doubt about being able to access secure sites after the update is significant. Lowering your security settings is not a good idea!

I hav't got the old firmware. I can access certain ssl like my rapidshare premium a/c and paypal, and my imagine a/c. Thery're all https.

clickbank is http://ssl.xxxxx.com these seem to cause problems.

I cannot connect to ssl sites with my router no matter which pc is used. The wierd thing is, I tried my dial-up modem, and it worked, so it looks like the problem is either my router or my isp. But i don't see why my isp would be blocking me, especially if i was able to access them before.

I have a Linksys wireless router and had a similar problem recently accessing anytimebanking from Ulsterbank.

I was advised to change the MTU setting of the router from 1500 down to 1400 and this has solved the problem.

I just tried it through a laptop with Windows Vista and it worked via the router, so it must be my OS.

It sounds like it might be a problem with the encryption settings on your browser. In your menu bar go to Help/About internet explorer and underneath the version number you will see "Cipher Strength" if this is less than 128-bit you wont be able to view many encrypted sites.
You can get an update for you your browser here