meeting disconnecting and reconnecting

Suddenly started getting disconnected and reconnected during meetings after years of trouble-free use. Happens every couple of minutes. I have to phone in to meeting after 5 mins, so I don't know if the connection eventually stabilizes. I'm using a chromebook, with upload speed of 30-35Mbps and download of around 5Mbps.

I've tried uninstalling and reinstalling the Zoom app; using an ethernet connection instead of wifi; connecting through browser rather than the PWA app. Nothing works. Any help appreciated.