I have seen this before if you are getting internet access through a service that requires you to visit an page to sign in first (for instance if you are at a cafe). Trying going to a site such as cnn.com that doesn't use ssl and see if you get a sign in page.

I had no problem opening the cnn.com page without signing in The problem is not solved.

You can try to reset the router.

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox (Tools) > Add-ons > Appearance/Themes).

• Don't make any changes on the Safe mode start window.
• https://support.mozilla.com/kb/Safe+Mode

cor-el..Thanks for you effort, but it did not work in the Safe Mode.