Can't get OK to work with an iPhone 12 mini

I’ve an OnlyKey Duo that works fine with my MacBook Air. I’ve not been able to get it to work with the iPhone. I’ve used two different USB-C to Lightning OTG adapters and neither works. The LED’s on the Duo do not light up so I’m guessing the device is not getting any/enough power. Is it a matter of trying it with different OTG adapters until I find the one that works?

Thanks!

I found that to be the case

Well that’s a little discouraging.

Thanks