bill and his blog

2FA and Gmail's "Send mail as"


This is a short story about how I configured myself out of my own email. Posting this as an exercise in humility, a tutorial for my future self in case of amnesia, and penance for my sins.


This allows me to use work and manage both of my inboxes as one. I recently added two-factor authentication (2FA) to personal, forgot about it, and spent a few days unable to send personal emails from any work device.


Whenever I tried to send emails on behalf of personal, I'd receive the following error message as a reply:

You're sending this from a different address using the 'Send mail as' feature. The settings for your 'Send mail as' account are misconfigured or out of date. Check those settings and try resending.

Useful error message if you ask me (especially in retrospect), but because I had forgotten that I setup 2FA for personal, I naively assumed this issue might magically disappear given enough time... kind of how restarting your device resets the state and causes the symptoms of a certain class of bugs to disappear.

After a few days of mounting frustration, I decided to take a closer look...


And now I'm back in business!