@TP-Link_Deco - Also, I have the TP-Link X20. Will there be a separate FW update for that model? I notice your link has "Deco_X60" in its name, so I'm guessing that firward update is only for the...

@TP-Link_Deco - is this new firmware generally available now? How do I upgrade my TP-Link Decos with this new firmware?

@TP-Link_Deco - That's great news. Thank you to the support or development team for investigating this issue and hopefully coming up with a fix. I'd love to have a general idea of the root cause of...

@ARegularGuy - I'm glad it was helpful. I also ran into this issue with the Mac Mail application, as that is the only email client I use. Thanks, David

@ARegularGuy - I've had the problem happen a second time. On my MacBook Pro laptop, I find if I turn off WiFi, and then turn it back on, the problem gets resolved. AFAIK, I've only had the problem...

@TP-Link_Deco - you quoted an Apple support article in your message. It is titled "Verify an email account’s outgoing server in Mail on Mac". The "outgoing server" connection is fine. That is SMTP....