First, please make sure that VPN In feature is enabled on the Roqos Core. You can verify this by going to VPN > VPN-In section in your Roqos Home app.
If your Roqos Core is behind another router, a likely cause of this issue is UPnP. If your Roqos Core is connected behind another router/modem (often provided by your Internet Service Provider), it requires that router/modem to open a port that allows access to your Roqos Core from outside. UPnP allows opening this port automatically. It is possible that UPnP is either disabled or not working properly on your upstream router/modem. If it is disabled, try enabling it and trying to connect again.
If UPNP is already enabled and you are unable to connect, you can create a port forwarding rule on your router/modem that points to the IP address assigned to the Roqos Core by your router/modem with the port designated for VPN In (The default port number is UDP 5052). You can obtain the IP address of Roqos Core by going to Settings > Advanced Settings > Internet Settings on the Roqos Home app. The IP address will be listed under the DHCP section.
For example if the Roqos Core is assigned the IP address 192.168.1.100, in your ISP modem/router, you should create port forwarding rule for UDP port 5052, pointing to 192.168.1.100. If your ISP router is asking for "Internal Port" and "External Port" separately, put 5052 in both of them. Every router/modem is different, so we recommend you refer to your router’s manual for creating a port forwarding rule.