Sometimes but not always when my computer iMac goes to sleep and then wakes, (Lightroom V9.3 has been open during this time) my identity plate in LH corner has changed to "Get started with Lightroom" rather than showing my name. Now the ability to sync my collections is not available and the Cloud icon in RH corner now has a X rather than a tick. I sync to iphone and ipad
This is just a guess but I think your hard drive that stores the catalog preset information has gone to sleep too. The monitor is coming back on before the hard drive wakes up, and Lightroom can't access the information.