Did this ever get resolved? My old core was on a 2010 Mac mini, which crashed. I bought a 2014 Mac mini and reinstalled Roon and backed up my database from a hard drive. Now the remote times out when trying to connect to the core :(.
Solved. Total operator error. I’d migrated to my 2014 Mac mini. Same account but technically, a differnt core. Duh! Once I “selected another core” from the app, it totally found it!