Step 5: Try Incognito/Private Mode

• Safari: Cmd+Shift+N
• Chrome: Cmd+Shift+N
• Firefox: Cmd+Shift+P

If it works here, it's a browser cache/extension issue.

Step 6: Disable Antivirus/VPN

If they're using any of these, temporarily disable:

• Malwarebytes
• Norton
• McAfee
• Bitdefender
• Any VPN software (ExpressVPN, NordVPN, etc.)
• Little Snitch
• Lulu firewall

Step 7: Check Keychain for Corrupted Certificates

1. Open Keychain Access (Cmd+Space, type "Keychain")
2. Select System keychain
3. Search for your domain name
4. If found, right-click → Delete
5. Restart browser