Error Parsing YAML File: Mapping Values Are Not Allowed Here

An improperly configured YAML file may show the error Error Parsing YAML File: Mapping Values Are Not Allowed Here . This error is demonstrated below:

Here is an example YAML file that causes this error:

application:application-id
version:1
runtime:php
api_version:1
threadsafe:true
#Error happens at line 7 below, even though the incorrect lines are above.
handlers:
- url: /example

Even though the YAML parser reports the error at line 7, the actual incorrect lines are above that point: lines 1 – 5 are missing the space character between the colon and the value. If you encounter this error, make sure that the key: value pairs are separated by 1 colon and 1 space character, as shown below:

application: application-id

Mail Service Error: Sender Is Not An Authorized Email Address

While using App Engine’s Mail API, some applications may encounter the following error:

This error means that the application attempted to send email with a non-whitelisted from address.

To send email from App Engine, applications must declare a sending address matching one of the following: a registered administrator of the application, the Google user account of the currently-logged-in user, or an email address of the form:

[any string]@[Application ID].appspotmail.com

For most purposes, using the appspotmail string as a from address is perfectly fine. To generate this sending address, you can use App Engine’s environment variables to collect the application ID. For example, here’s how to do it in Java:

String application_id = SystemProperty.applicationId.get();
String sender = "[email protected]" + application_id + ".appspotmail.com";

For applications that need to send email originating from their custom domain, register a Google Apps account with the address you want to use, then register it as an administrator of the application.