I bought the EU868 RAK Wireless Gateway Discover Kit that included everything I use (https://bit.ly/2YFrY70).
So I believe that everything is operating at the right band. The gateway:
Is it ok to use it like this?
The node is equivalently used at its default config (its included antenna has a sticker writing 868 Mhz) as in the product picture.
I am testing inside a building and sure there are walls and doors, but building materials are normal concrete/bricks; it should work at a range of 30-50 meters right?