I was having no problem connecting my Roon Remote app on my iPad to my Roon Core until I connected my Arcam AMP as a new audio device in Roon - now the app cannot locate the Roon Core on my Microsoft Surface laptop - the Roon app on my laptop is working fine but would be convenient to be able to also access and use Roon on my iPad using the Roon Remote app - would not seem to be a Network or Firewall issue given the Roon Remote app was working find on my iPad until I added the Arcam amp as a new audio device on the Roon on my laptop
Welcome to the forum and apologies for the slow response here.
I have not heard of such an issue happening before where an audio device would cause a connection problem. You are saying that if you remove the ARCAM, then the Core starts to be discoverable by the iPad?
I know you said that the firewall hasn’t changed, but Windows updates can sometimes reset firewall settings, so I would confirm this explicitly. Since you are using a Windows PC, I would verify that both Roon.exe and RAATServer.exe have been added as exceptions to your Windows firewall.
You can use these instructions to add the exceptions and the executables themselves would be located in your Database Location/Application folder path.
I would also add these exceptions to any Antivirus or other Firewall blocking applications you may have and ensure that you connected to your network via a Private network, not a Public one, see this guide for more information.