Java – although there are no errors in the log, the email sent on Google App Engine is invalid

[I looked at all the questions related to this topic on so, but none of them seemed to explain the behavior I saw]

I have two projects a (3-4 months old) and B (0.5 months old). Both projects use general courses to send e-mail on Google App Engine Both projects are currently running in free quotas

When I call the public emailer class from project a, an email will be sent; Calling from B will not produce any errors in the log file (the log displays the correct information in the e-mail field), but the e-mail will never reach the recipient address I checked the spam folder / tag and even searched the entire mailbox for mail from: appspotmail (see below), nothing. Www. 68mn

I have confirmed that for each email sent, the email quota on the developer console (in console. Cloud. Google. COM / appengine / quotadetails? Project = project-b \ u0026amp; moduleid = default) registers another recipient, so it is obvious that Google Code is being called correctly (the email in question is to reset the password, so only the recipient)

I tried to send as admin@mydomain.com ( admin@mydomain.com The email API (authorized senders list) that has been added to the settings page of APP B is also used as admin@project -b.appspotmail. COM, but neither is valid

So far, on project a, I have always sent e-mail for admin@project -a.appspotmail. Com (where project - A is the ID of my gae application), and I have never encountered any such problems

What happened here? Did I miss some extra settings?

Note: this may not have any impact, but it is mentioned for completeness: the format of the recipient's e-mail address is myaccount xyz@gmail.com , not more common myaccount@gmail.com. However, sending email to this address manually from Gmail is valid, so this should not be a problem

Update 1

Based on the suggestions here and what I've tried since I posted this question, here are some updates:

>I have set up an email return handler as suggested, but it has not been called (according to the log)

Maybe it will be called after waiting 24-48 hours Let's see. > Use email simplename@gmail.com Set up the account and call the forget password function exactly the same (i.e., no). > Change sender email to admin@project -name. appspotmail. Com (instead of project ID) and receives an unauthorized sender email in the exception

This means that other addresses I've tried are authorized senders because I've never seen any exceptions to them

Solution

The best way to solve the email delivery problem of APP engine is to configure email bounce notification Because e - mail is delivered asynchronously, any delivery problem will cause the specified sender to return it