I have been having connection difficulties of various types since updating to Firefox 15.0.1 a few days ago.
Firefox crashes or stalls for several minutes. Certain sites, typically sites using SSL/https, generate the message page you describe. They warn that the certificate can’t be verified. Offer you the option of proceding ahead but warning against it.
I tried several things to clarify the issue. I pursued many dead ends and wasted a lot of time.
I finally took a careful look at the certificate store. You can do this directly from Firefox as follows:
Tools > Options > Advanced Tab > Encryption > View Certificates
This will open Certificate Manager. Click on the Servers tab. Scroll down to “The USERTRUST Network.” (When I tried to go to The USERTRUST Network on the internet, I was redirected to Comodo, so I’m assuming they are part of the same entity). Click on any of the items in this category. All of the items in this category are every day organizations we all depend on. But take a look - for example at the item www.google.com . Click on the details tab. On this tab, click on www.google.com. Then notice the description field. It reads: Token:Bogus Google.
The certificates in this category are all issued by USERTRUST. But all of these certificates are labeled as "Bogus . . . "
These certificates are not just contained in Firefox. Open Windows Certificate Console. Move to the category “Untrusted Certificates.” These same certificates are listed as “Untrusted” or “Fraudulent.”
I have tried several procedures to get rid of the problem. I deleted what I assumed to be wrongly installed fraudulent designations on these certificates. I ultimately completely uninstalled Firefox, deleting all user settings, addons and any remaining items in the program and user data folders. I then reinstalled Firefox. The problem remains there unchanged.
So I finally began to consider that Comodo really has designated these certificates as fraudulent. Indeed, it looks like Comodo and Firefox are using what appears to be an innovative way of handling certificates. It allows the software to check up on just one certificate (instead of having to download an entire list of revoked certificates). But something has gone wrong. And . . . there doesn’t seem to be any way to turn it off!
The best way to describe Comodo’s role in the problem is to again look at the details pane of one of the certificates. Notice the “Authority Information Access” item. This is the address where your software is supposed to be able to check up on just the one certificate at a time. The URL is http://ocsp.comodoca.com. It turns out that Comodo itself blacklisted is own ocsp folder a few months ago. OK. I say very good. Sounds like a responsible company.
But a responsible company would also be taking steps to notify people who are being tortured by the fallout from this problem. Disappointingly, upon at last finding my way to Comodo’s site, I search for references to Firefox, comodoca, etc. There is nothing to be found.
Where’s the help. And why are fraudulent certificates being reinstalled in my Windows Certificate Store when I reinstall Firefox?
This problem has forced me to invest many hours tracking down the source. And, though its not often that one feels sorry for ones cable internet service provider, their technician concluded it must be their fault. He installed a new and upgraded router, new wiring. And they didn’t charge me because they figured it their equipment causing the problem.
Comodo needs to offer some help with this.