Telus email on MacBook broken - connections to host imap.google.com failed

Hey all, it worked for a couple days then my Telus email broke again in Apple Mail. So here's the story ...  Slightly different problem than before, now it was Send Mail that wasn't working. Receiving mail still worked. The error message was, "Cannot send message using the server ****@telus.net.  The sender address was rejected by the server smtp.gmail.com. The server response was: Authentication Required."  In Mail -> Preferences -> Accounts, tried re-entering the password multiple times, but no luck. Tried generating another App Password in Google, but still no luck. Finally, in the same message prompt as above, went into "Edit SMTP Server List", and found multiple entries for my ****@telus.net email address. Figuring this might be the source of confusion, I deleted them all, went back to Accounts, and removed the Telus email account (clicking the "-"). Am using IMAP so this only removes the account in Apple Mail, doesn't delete the actual Google email account. Then I re-added it using these instructions: 

https://www.telus.com/en/support/article/set-up-email-on-devices. Briefly, it's Mail -> Add Account, then follow the steps. It does't require an App Password; you authenticate in a browser logging into Google and allowing MacOS access. And presto!  My Telus email account was back in action in Apple Mail. So not sure exactly what went down here, but fun waste of a nice afternoon with Telus email powered by Google 😬.