I have to wonder if there is an issue with the BOOST, although I’d think the Move would still show up.
Try moving your Ethernet cable from the BOOST to a regular Sonos speaker temporarily, avoiding a surround or Sub), an report back.
Have there been any changes recently? New neighbors? Updates to your ISP’s router?
Have you submitted a system diagnostic within 10 minutes of experiencing this problem, and called Sonos Support to discuss it?
There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.
When you speak directly to the Support staff, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.