Here are steps to troubleshoot QuickBooks Error 9000:

1. Check Internet Connection: Ensure you have a stable and active internet connection.
2. Adjust Security Settings: Temporarily disable any firewall or security software. Make sure your system’s SSL settings are set to “Use SSL 2.0” and “Use SSL 3.0”.
3. Update Internet Explorer Settings: Ensure your Internet Explorer settings are correct. Go to “Internet Options,” select the “Advanced” tab, and check “Use SSL 2.0”