Step 8: Update macOS

1. Apple menu → System Settings → General → Software Update
2. Install any pending updates
3. Restart Mac

Step 9: Reset Network Settings

1. System Settings → Network
2. Select active connection (WiFi/Ethernet)
3. Click Details → TCP/IP
4. Click Renew DHCP Lease
5. Go to DNS tab
6. Add Google DNS: 8.8.8.8 and 8.8.4.4
7. Click OK and test

Step 10: Check for Proxy Settings

1. System Settings → Network
2. Select active connection → Details
3. Click Proxies tab
4. Ensure all proxy options are UNCHECKED
5. Click OK

Step 11: Test in Safe Mode

1. Restart Mac while holding Shift key
2. This disables third-party extensions/software
3. Test your site
4. If it works, a third-party app is interfering

If nothing else works:

Diagnostic Command

Run this in Terminal and send the output:

curl -vI https://summarytools.cc 2>&1 | grep -E "(SSL|TLS|certificate|error)"