On-premise Data Gateway not listed

I have a similar problem as described in theis thread:

https://community.powerbi.com/t5/Integrations-with-Files-and/On-premise-Data-Gateway-does-not-work/m-p/62178#M5029

But I not sure I understand the solution!!?? I have downloaded and installed my on premise data gateway and assigned it to my Power BI. But the gateway is NOT listed. I have the same screen shoot as in the link referred to above. Can this be a security issue? I am using a Office 365 Trial and Microsoft Account, NOT a working account. Could that be the issue. I have tried to install the Gateway from 2 different machines and same result.

TIA

Bobby