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