Error: Invalid registry endpoint ... Get ... If this private registry supports only HTTP or HTTPS with an unknown CA certificate, please add '--insecure-registry 192.168.1.103:5000' to the daemon's arguments. In the case of HTTPS, if you have access to the registry's CA certificate, no need for the flag; simply place the CA certificate at /etc/docker/certs.d/192.168.1.103:5000/ca.crt