You only get a limited number of concurrent connections for ALL of your devices. Do you have any other devices connecting to the mail account? Turn them off for 10 minutes and see if that fixes the issue.

Thanks for your prompt reply Matt. The only other devices I access gmail from is another laptop (I log out of my gmail account when I'm done), a gmail app on a Nox android emulator that I hardly ever open & blue mail from the microsoft store, that also has the same problem.

what is the error message verbatim. I can think of a number of possibilities here, none of them great, but having the exact message with server name might narrow things down.