Test email keeps on failing

Hi, Jason.

I just installed your plugin and configured it according to the video you have posted. Everything seems to work OK, but when I try to send a test email, the error I get is:

Sending the message: Failed

The plugin otherwise is sending out emails correctly.

Could you please look into this? My installation info is:

OS: Linux server93.web-hosting.com 2.6.32-531.17.1.lve1.2.58.el6.x86_64 #1 SMP Wed Jun 18 08:28:56 EDT 2014 x86_64
HTTP User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:39.0) Gecko/20100101 Firefox/39.0
Platform: PHP Linux 5.3.29 / WordPress 4.2.2 en_US
PHP Dependencies: iconv=Yes, spl_autoload=Yes, openssl=Yes, sockets=Yes, allow_url_fopen=Yes, mcrypt=Yes
WordPress Theme: News Pro Theme
WordPress Plugins: Advanced Menu Widget, Akismet, BackWPup, BAW Login/Logout menu, Broken Link Checker, Contact Form 7, Email Obfuscate Shortcode, Export Users to CSV, Genesis eNews Extended, Genesis Simple Edits, Genesis Simple Hooks, Genesis Subpages as Secondary Menu, Genesis Tabs, Genesis Visual Hook Guide, Google Doc Embedder, Google XML Sitemaps, Jetpack by WordPress.com, MemberPress Business Edition, Menu Items Visibility Control, Multi Author Comment Notification, Postman SMTP, Simple Social Icons, Simple Staff List, TablePress, TinyMCE Advanced, Username Changer, Widget CSS Classes, Widget Logic, WordPress Access Control
Postman Version: 1.6.23
Postman Sender Domain (Envelope|Message): akuaana.org|akuaana.org
Postman Prevent Message Sender Override (Email|Name): No|No
Postman Transport URI: smtp:tls:oauth2://smtp.gmail.com:587
Postman Transport Status (Configured|Ready|Connected): Yes|Yes|Yes
Postman Deliveries (Success|Fail): 0|0
Postman Bind (Success|Fail|Path): Yes|No|/home/akualum/public_html/wp-content/plugins/postman-smtp/Postman/PostmanWpMailBinder.php
Postman TCP Timeout (Connection|Read): 10|60
Postman Email Log (Enabled|Limit|Transcript Size): Yes|10|128
Postman Run Mode: production
Postman PHP LogLevel: 40000
Postman Stealth Mode: No
Postman File Locking (Enabled|Temp Dir): Yes|/tmp

Best regards,

https://www.ads-software.com/plugins/postman-smtp/