I use the Cubase IC Pro iOS app all the time, to control transport, mix, etc., via an iPad and/or iPhone, e.g., recording away from the chair at the DAW. It works fine in Cubase 10.5. in Cubase 11, the app sees the DAW computer, but never comes back, i.e., sits and spins forever trying to connect.
I’m using the current iOS app.
DAW is on MacOS Mojave 10.14.6
Same system here. On 10.5.12 at the moment, hopefully this get sorted out. 
Same here on my PC. There’s a new Bonjour download on Apple, I’ve updated this but still no joy. I suspect this was overlooked by Steinberg?
here’s a weird workaround: fire up C10.5 and connect with your iOS device using the Cubase IC Pro. the. shutdown C10.5 and start C11. it stayed connected for me.
imho this gives weight to a Boniour issue.
Please check your firewall and system security settings. There should be no difference connection to Cubase 10.5 or Cubase 11 from Cubase iC Pro.
…and yet there is 
my LAN has not changed and i find it unlikely that several others would have changed their LAN when upgrading Cubase, either. mr.roos says there’s a new Bonjour; perhaps the issue is because nothing changed in the SKI code? maybe y’all are compiling with an old version of Bonjour?
while you’re there, you might wanna try setting/changing SKI passwords - that can crash, too.
Here’s another thought to the Steinberg ppl. The new Bonjour print app I installed yesterday (version 2.0.2.0) runs my WIFI printer in another room without a problem - which tells me there is no firewall block. Also, looking at my ‘Allowed Apps’ in the Defender Firewall, both Bonjour services are checked, for Private and Public networks.
Maybe it’s time to update the Steinberg Ski Remote app?
You have to allow Cubase to talk with the iPad in your firewall settings. Otherwise the communication is blocked by it. Bonjour is only used by iC Pro and Cubase to find each other.
Hm. What? I’m using my iPhone 8 btw, and it works in C10.5. What would I do to my iPhone to let it talk to Cubase11?
You have to do the same you did for Cubase 10.5.
Arne, now you’re speaking like Yota and I’m not sure if you’re trying to be funny or helpful. I don’t think you are reading these posts?
Here: If the same Win10 PC that has BOTH C10 and C11 installed on it, allows the iC Pro app to work with C10.5 then it WOULD SEEM that it has to work in C11. BUT IT DOESN’T. Arne, you suggest to change something in Win10… but there is no unique change to be made within Win10 to allow the firewall to create a different or new path for an iPhone (or an iPad) that it already recognizes.
So, something is wrong with C11, not Win10. Please sort this problem and help the users of the iC Pro app.
Really, I try to help you. There’s nothing changed in Cubase 11 in regard of the iC Pro integration. If you have enabled the Windows firewall then you must have made changes to make Cubase 10 work with the iPad/iPhone and this changes must normally be done for Cubase 11 too. Just for a test, does your connection work if you temporarily disable the Windows Firewall? If yes, then you have to check your settings there. If this does not fix it, then I’m out of ideas.
I just tested this on a fresh mac mojave system…
(Early 2015 mbp)
-download ski remote, install
-add in devices
-connect to app
Works fine so it must be something else… - i assume you need to re-install the ski-remote from the steiny website, but im just guessing)
-what ios versions are you all running? (Im still on 12.4.1)
Hope this helps:)
(Ski Site instructions needs to be refreshed for new versions btw)
Alright. I turned my Win10 Firewall off and the Ski Remote DOES work in C11. So thank you for suggesting this. However I need to turn it back on - so I will do this for each domain until I find the one that blocks the Ski Remote. If I fail in this I will contact MicroSoft… It still seems very odd to me that I can contact my HP printer through the same Firewall but not C11. Is the fault with Windows or Steinberg?
And a follow up, it seems to be the Firewall to the Public Domain. I will contact MS and see what they have to say about this.