How to send mail on behalf of Google apps address with Gmail?

Question

Context

I got a Google apps for my-google-apps.com and what to be able to send mail on behalf of this domain through my Gmail address that I use as primary address.

Settings

• Send mail as: Coding Goûter <[email protected]> ;
• Mail is sent through: smtp-relay.gmail.com ;
• Secured connection on port 587 using TLS.

Error

Delivery to the following recipient failed permanently:

     [email protected]

Technical details of permanent failure:
read error: generic::failed_precondition: read error (0): error

----- Original message -----

X-Gm-Message-State: ALyK8tKwKBrOQHPiS4ZRUe54UUxBmujgWZw20aXORPT2T3wvaMYh8keekpQmHw1bQj/clA+dprC+WZ0TJUYwEg==
X-Received: by 10.25.23.8 with SMTP id n8mr2876085lfi.205.1468225620148; Mon,
 11 Jul 2016 01:27:00 -0700 (PDT)
MIME-Version: 1.0
Received: by 10.25.146.142 with HTTP; Mon, 11 Jul 2016 01:26:20 -0700 (PDT)
From: =?UTF-8?Q?Coding_Go=C3=BBter?= <[email protected]>
Date: Mon, 11 Jul 2016 10:26:20 +0200
X-Gmail-Original-Message-ID: <CAHGFyZTgbiKGQnm4OB8Sin5VobfTCawshodU+srw71LgKeu2XQ@mail.gmail.com>
Message-ID: <CAHGFyZTgbiKGQnm4OB8Sin5VobfTCawshodU+srw71LgKeu2XQ@mail.gmail.com>
Subject: test
To: [email protected]
Content-Type: multipart/alternative; boundary=001a114080488a0724053757ea31

Question

How do I setup this? Is the SMTP configure incorrect?

Answer 1

Check the following

1. use Gmail SMTP server ;

   Gmail SMTP server - requires authentication with your Gmail/Google Apps account and password. Messages can be sent to anyone inside or outside of your domain.

2. (not sure) enable Allow less secure apps: ON setting.

Config

• Send mail as: Coding Goûter <[email protected]> ;
• Mail is sent through: smtp.gmail.com ;
• Secured connection on port 587 using TLS.