Error sending e-mail via SMTP server on App Engine development server

Question

I am trying to send Email using this sample code and these command-line options:

dev_appserver.py --smtp_host=smtp.gmail.com --smtp_port=25 --smtp_user=xxx@g         


        

Answer 1

The Google account being used to send emails from an application must have some security settings disabled in https://security.google.com/settings.

• Disable access for less secure apps : Access for less secure apps: Turn On

If you continue to have authentication issues you may have to review the Devices & activity at the https://security.google.com/settings/security/activity

Answer 2

dev_appserver.py doesn't support TLS which is required by Gmail. You can enable it by adding a few lines in api/mail_stub.py:

# After smtp.connect(self._smtp_host, self._smtp_port)
smtp.ehlo()
smtp.starttls()
smtp.ehlo()

Note! That's the quick and dirty solution. You should add some kind of flag to tell it whether you want to use TLS or not, as it is not always desired.

Answer 3

@Raymond

Execute the following command in the Terminal:

find / -name "mail_stub.py" -type f 2>/dev/null

In my case it returns:

/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/api/mail_stub.py

Answer 4

For anyone looking up this answer in 2018 or later: this workaround is no longer needed. You can now use the command like the original poster wrote it:

dev_appserver.py --smtp_host=smtp.gmail.com --smtp_port=25 --smtp_user=xxx@gmail.com --smtp_password=yyy myapp

Answer 5

The other methods are no longer necessary:

Setting the following in /appengine/api/mail_stub.py

if self._allow_tls and smtp.has_extn ('STARTTLS'):
  smtp.starttls ()

works for me on appengine sdk version 1.9.15