I cannot connect my mobile phone to the system. Up until this afternoon I had the same problem with Sonos, but after changing from 2.4 GHz to 5 GHz wifi that problem disappeared. However the same trick did not work with Roon.
In order for Roon’s @support team to better assist you, please provide a brief description of your current setup using this link as a guide.
Make sure to describe your network configuration/topology, including any networking hardware currently in use, so they can have a clear understanding of how your devices are communicating.