Tons of factors lead to ‘Error 12007 QuickBooks’. There is a problem connecting the computer to the internet. A network timeout prevents QuickBooks from connecting to the database. Your connectivity is blocked due to the firewall setup. In Internet Explorer, the SSL Tickbox may well have been deactivated. Check the Internet Connectivity first to see whether that's the problem. After that, choose "Advanced Network Settings" from the "Next" menu. Select "Internet properties" from the drop-down menu. Follow on-screen instructions.