Cosy131 showing as offline while connected

Good afternoon,

We have a Cosy131 which is connected to a clients network via Wan for Internet, and Lan for PLC access,
The unit has been registered on T2M however the device is not connecting to the internet, showing as offline when attempting to access.
The Wan network would have internet access available, just wondering if there is a specific firewall setting that could be preventing this on the clients network?


Here are the hostnames with the IP addresses we use for are connection to the server. There is also a connection checker tool they can try running on a computer that has the same WAN connection as the Cosy 131. to see at what part it fails.