Q: Safari will only connect with https sites

Try rebooting your router.

Safari - Unsupported third-party add-ons may cause Safari to unexpectedly quit or have performance issues

Safari doesn't load a page or webpage items are missing

Safari/other browsers – Website not loading

Have you installed something called "Avast," or any other kind of "security" or "anti-virus" software?

Please back up all data.

From the menu bar, select

           ▹ System Preferences... ▹ Network

If the preference pane is locked, click the lock icon in the lower left corner and enter your password to unlock it. Then click the Advanced button and select the Proxies tab. If any proxy options are selected, make a note of them and then deselect them. You don’t need to change the bypass or FTP settings. Click OK and then Apply. Test. The result may be that you can't connect to any web server. Restore the previous settings if that happens.