What security software do you have?

Did you make sure that your security software isn't blocking access?

You can also check for malware.

• https://support.mozilla.org/kb/troubleshoot-firefox-issues-caused-malware

I don´t have an antivirus installed. If I restart Firefox I can go to google.com once, just once, after that, the same: "Connecting..." and "Waiting for www.google.com..." and nothing again.

Did you try to search for malware?

Create a new profile to test if your current profile is causing the problem.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

Thanks for your replies. I tried the creating a new profile suggestion, but nothing worked. I gave up. I'm giving Vivaldi a chance right now.

Start Firefox in Safe Mode {web Link} by holding down the <Shift>
(Mac=Options) key, and then starting Firefox. A small dialog should appear. Click Start In Safe Mode (not Refresh).

Is the problem still there?

The problem still there (

Start your Computer in safe mode with networking. Then start Firefox. Try Safe websites. Is the problem still there?

Starting The Computer In Safe Mode;
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