Sendgrid is a great alternative and not hard to set up.
Google App Engine Silently Stopped Sending Email 5 Weeks Ago
11–20 of 119 posts
Re: Google App Engine Silently Stopped Sending Email 5 Weeks Ago
#12Re: Google App Engine Silently Stopped Sending Email 5 Weeks Ago
#13At least a few reported that it was bouncing at the destination once they set up an appropriate handler. They are only "not being sent" when there is a url in the message and that is a big red flag on the receiving side (not much text but a url). It doesn't look like an App Engine problem. It looks like messages being identified as spam problem.
Nothing whatsoever changed in my code. I haven't touched it in a year, and all of sudden email stopped on the 1st of April.
There's nothing in the changelogs to indicate there was a change that should cause this behaviour. It's absolutely an App Engine problem.
https://cloud.google.com/appengine/docs/python/release-notes
Re: Google App Engine Silently Stopped Sending Email 5 Weeks Ago
#14Re: Google App Engine Silently Stopped Sending Email 5 Weeks Ago
#15Re: Google App Engine Silently Stopped Sending Email 5 Weeks Ago
#16Reading through the thread, it looks like in the last few days it's been narrowed down to "messages which contain the URL of the App Engine instance silently disappear with no bounces or errors."
Re: Google App Engine Silently Stopped Sending Email 5 Weeks Ago
#17Re: Google App Engine Silently Stopped Sending Email 5 Weeks Ago
#18Re: Google App Engine Silently Stopped Sending Email 5 Weeks Ago
#19Re: Google App Engine Silently Stopped Sending Email 5 Weeks Ago
#20Reading through the thread, it looks like in the last few days it's been narrowed down to "messages which contain the URL of the App Engine instance silently disappear with no bounces or errors."
And only sometimes. The issue resolved itself on my app two weeks ago. My guess is there is an outgoing spam filter run amok in some of the clusters.