Could a VPN interfere with Chrome's secure connections and cause this error?

Yes, a VPN can sometimes interfere with secure connections and trigger the 'err_ssl_protocol_error' message. VPNs encrypt your internet traffic and can sometimes cause conflicts with the SSL/TLS handshake process. Try temporarily disabling your VPN and see if the error disappears. If it does, you may need to adjust your VPN settings or choose a different VPN provider.