You might get this message in Google AppEngine when sending an email message and specifying a custom from address. To get it to work you must add the address as a developer for your application (or use the email address you signed up with).
Steps to Add a Developer Email Address:
- Log in to your Google App Engine Account.
- Under Administration, click Permissions, and add the email address.
- Log out, and check for the validation email.
More Info:
This is quite a hassle. I understand the reason is to cut back on spam but not only do you have to have a valid email account but you must create a google account for it.
In my case, I just wanted to send notifications out but I don’t monitor the sender address (but I do include a contact link in the email).
Darn spammers!


April 22nd, 2010 at 1:59 am
Thank god someone took the time to detail their solution. Much appreciated!
April 25th, 2010 at 11:49 am
Strange – there is no “Developers” under the Administration section.
I am using Google Apps authentication.
April 30th, 2010 at 4:11 pm
It it is now under ‘Administration -> Permissions’. I fixed the post. Thanks!
August 7th, 2010 at 9:00 pm
Great job, easy to following instructions. May god bless you.