I hope this is helpful to someone; I am already in contact with Revopoint support about the issue.
My POP3 was working in 3DViewer; I was curious about the new RevoScan update and ran that; it prompted me to update of the POP3, which I did, hoping for better performance, possibly.
Unfortunately my POP3 does not connect anymore now in 3DViewer.
I am in contact with Revopoint; the cause of the issue is not clear yet. From the 3DViewer application log, it seems that the camera authorization may have coincidentally expired right about the time I updated the firmware; re-authorization has not been successful however. So no solution yet.
Happy to report this issue has been solved: it turns out the camera authorization had expired right around the moment I updated its firmware; to get it re-authorized an update of RevoLicenseWizard to version 1.0.10 was necessary.