Screen mirror from iPhone not working

I just tried my Express 4K+, and it worked immediately after I entered the code. I had never tried screen mirroring this phone to that Roku before, so there was nothing preconnected for either device. This was an iPhone 13 running iOS 18.1. Since that was my work phone, and it has some enterprise restrictions on it, I then tried my iPhone 16 Pro Max. It was running iOS 18.0.1 (didn't realize it hadn't updated yet) but it too connected immediately. My Roku is on OS 14.0.

I will also note that while both phones and the Roku are all connected to my home network, the two phones were connected to different access points in my home. So don't let anyone tell you that the devices must be connected to the same access point and/or the same WiFi band. I have specifically tested in the past with either the phone or the Roku on 2.4 GHz and the other on 5 GHz, and it worked just fine. 

Is your Roku defective? I can't say. However, based on your model number having EU at the end, it's possible that AirPlay might not be available outside North America. I don't know that for a fact, just as a possible reason for it. I couldn't say if that is a Roku issue or Apple. Since you provided a problem ID number (great of you to do that!) Roku should be able to check the logs and see what is going on.