I have a GMail account, and I access it from two Macs, and an iPhone. The iPhone and one of the Macs (10.14.x) still works.
On the other Mac (10.13.6), it stopped being able to receive mail a couple days ago. The "Mail Connection Doctor" says "Trying to log in to this IMAP account failed. Verify that the username and password are correct", and likewise for SMTP.
I found some ideas online and tried them, but nothing so far has worked:
- Go to https://myaccount.google.com and turn on "less secure account access" (it was already on)
- Go to https://accounts.google.com/b/0/DisplayUnlockCaptcha
I haven't changed my password in the past month, and I can still log in to GMail with a web browser.
When I go to "Accounts" in Mail.app and click my GMail account, it presents an OAuth-like sheet asking for my Google email/password. When I complete the form, the sheet turns gray (empty), and only the "Cancel" button remains.
I found reports that GMail broke on Mojave recently, but my pre-Mojave system is the one that broke.
Any ideas for how to make this work again?
UPDATE: I've been clicking "Check Again" several times, and one time I got IMAP (only) to work, and it downloaded this week's email, but then it stopped working immediately. I don't think I was doing anything special that time.
In the "Detail", I see:
250-smtp.gmail.com at your service, [my.ip.address]
{many more 250-prefixed lines}
AUTH LOGIN
334 VXNlcm5hbWU6
{my b64-encoded email}
334 UGFzc3dvcmQ6
*
501 5.5.2 Cannot Decode response {big_ugly_code} - gsmtp
QUIT
That's not my password -- it really just says *
there (though I don't know if Mail.app substitutes that in the window for safety).
UPDATE 2: Calendar.app has all my latest calendars, for this same Google account, and syncs fine on this computer (though obviously not with SMTP or IMAP).