This means your server has difficulties communicating with our server. In most cases the reason for this is that there are restrictions on outgoing connections on your server, e.g. because of a firewall. Please ask your hosting company / server team to either a) temporarily de-activate the firewall (port 443) for a minute (at least the outgoing connections) or b) whitelist 188.165.53.179 and 192.81.249.240 as IPs so that your server can communicate with our server.