Mail on Mac will not connect to Gmail servers
A week or so ago Mail on my iMac stopped connecting to my Gmail servers. I have followed every single piece of advice/suggestion I can find on this community site and others to get back to normal but without success. Curiously, I can no longer even see outgoing and incoming server information on my mac and therefore have no settings to "change". I have no problem at all with Mail my iPhone and iPad. There must be a simple explanation for this - and, yes, I have checked everything on the Gmail end and the mac end. Any bright ideas?
My mac is a 27" late 2013 running macOS Catalina 1-.15.7 (which cannot be updated to Big Sur or Monterey) and Mail is version 13.4. Although I have had other issues recently (e.g. TimeMachine - which I have fixed, and inability to connect to a Sonos system - which I have not yet been able to fix), the mac works just fine apart from this new, out-of-the-blue mail failure.
iMac