Cannot connect to Intergas GW, from Opentherm_gw

I am trying to use the HA Opentherm gateway integration to connect to an Intergas gateway II.
When I have entered:
Name : “HeaterGW”
Path or URL: “gateway IP address”
ID: “heaterGW”
I always get “failed to connect”

Note: I can connect to the Gateway using the HA incomfort integration.

It is probably because HA needs to authenticate to connect to the Intergas gateway.
Can anyone point out where to enter username/password?

Or am I missing out anything else?