Infuse on Apple TV can't see my AirPort Extreme

I have just purchased the Pro version this evening and I cannot get the app on my Apple TV to detect my AirPort Extreme. I have the latest gen Apple TV and AirPort Extreme.
I have tried manually adding a ‘Share’ but I constantly get the same connection error message.
I’ve already looked for the answer online but I cannot find one. I’ve tried all different combinations of usernames, IP Addresses and passwords but I’m unable to connect.
Can anyone suggest why the Airport Extreme isn’t showing up as a detected item in the Infuse app for starters.

Thanks.

Have you looked at the set up info at https://support.firecore.com/hc/en-us/articles/215090977-Streaming-From-Other-Devices and primarily the info for Device specific notes at the bottom of the page regarding the Airport Extreme?

Yes I have already been through the ‘setup’ and followed what it asks. It assumes that everything connects and doesn’t offer any help or advice if it doesn’t.
I do have file sharing activated on my AirPort, I do know that password, I’ve already tried the basic stuff like that.

You havne’t provided any details of your setup.
How is the network setup ?