How to connect Yamaha receiver to iPhone via Wi-Fi?

I am using the Yamaha AV controller app from the apple app store which controls my Yamaha receiver. Both my receiver and iphone are on the same wifi network. Yet when the Yamaha AV controller app on my iPhone tries to connect to my receiver it says the device does not exist.

I'm new to apple products and have no idea why this is happening. It works just fine from any of my android devices using the same app.

Any help would be greatly appreciated.

[Re-Titled by Moderator]