Same happened for me today.
Reposting instructions from above (it helped me navigate to the solution):
https://community.roonlabs.com/t/introducing-the-roon-early-access-program-help-us-test-roon/222752
Apparently I had to move all my controllers to the Early access version (hasn’t changed in Arc for me yet though) - That is to say I needed to download the early access version of Roon on my laptop, and install Testflight and the early access for IOS on both phones. Deleted Testflight once complete. Worked a treat.
R