Mail goes through but error from Gmail api

I have your plugin configured on a few sites and have become familiar with the settings. I like the new look by the way.

I wanted to just let you know this error I am getting. It says there is an authentication error, but i can not find where to enter correct information. I have checked the plugin and the google api console.

but here it is, perhaps you have seen it. Keep in mind I do get the email. It just comes delivered with a second email with the information below.

Jamie

======ERROR=======

Delivery to the following recipient failed permanently:

[email protected]

Technical details of permanent failure:
Google tried to deliver your message, but it was rejected by the relay mail.txtdir.com by mail.txtdir.com. [69.167.158.73].

The error that the other server returned was:
535 Incorrect authentication data
(SMTP AUTH failed with the remote server)

—– Original message —–

X-Received: by 10.25.135.133 with SMTP id j127mr4102697lfd.73.1448065008031;
Fri, 20 Nov 2015 16:16:48 -0800 (PST)
Received: from 587696054206-1umlvvgcd9h6t1fs5a8dnlr9edm7hvu7.apps.googleusercontent.com
named unknown by gmailapi.google.com with HTTPREST; Fri, 20 Nov 2015 19:16:47 -0500
X-Mailer: Postman SMTP 1.7.2 for WordPress (https://ww.wp.xz.cn/plugins/postman-smtp/)
From: TxtDir Admin <[email protected]>
Sender: [email protected]
MIME-Version: 1.0
Date: Fri, 20 Nov 2015 19:16:47 -0500
X-Google-Sender-Auth: pQ4riWe4Uw_wzHCprCHS9eTwVaM
X-Gmail-Original-Message-ID: <CABB7RtkXn-5QrGs1+STREkip3CVPaEKgOWHAPtUZnZLcbCVaXg@mail.gmail.com>
Message-ID: <CABB7RtkXn-5QrGs1+STREkip3CVPaEKgOWHAPtUZnZLcbCVaXg@mail.gmail.com>
Subject: Postman SMTP Test (txtdir.com)
To: [email protected]
Content-Type: multipart/alternative; boundary=001a113fc1da6a6264052501e84d

Hello! – 你好 – Bonjour! – नमस्ते – ¡Hola! – Olá – Привет! – 今日は
Sent by Postman 1.7.2
https://ww.wp.xz.cn/plugins/postman-smtp/

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