Using Gmail for outbound email from Plone sites

I just ran into this problem today, with a Plone 5.0 site. I configured it in the Mail settings panel to send email using a Gmail account. The account does not have 2 factor authentication enabled, and I know I entered the correct password. The error displayed when I used the "Save and send test e-email" button was:

Unable to send test e-mail (534, '5.7.14 Please log in via your web browser and\n5.7.14 then try again.\n5.7.14 Learn more at\n5.7.14 133sm7809684qhu.9 - gsmtp').

That page at mentions "Your app might not support the latest security standards".

The page at describes Gmail's tightening of security. I've enabled the "Allow less secure apps" setting but am still not able to send out email from the site.

Any thoughts on how we can make it less irritating to use Gmail for outbound emails from Plone?


The first time I enabled "Allow less secure apps" it did not stick. I reloaded the page and tried again and it worked, and I was able to send out email from the Plone site.

I'm running into this problem on another Plone site (this time, Plone 4.3), and trying what I did above didn't work. I definitely have the correct password (2FA is not enabled for that gmail account, tsk tsk), and "Allow less secure apps" is on.

If anyone else has run into this, how did you fix it? Is it a question of reverse DNS? Do I have to create an SPF or DKIM record?