Not sending mail – no error

I am hosting my WordPress site on an AWS server running Ubuntu. The plugin is installing correctly, and I have no problems granting access with the API, however when I try to send a test email, there is no apparent error in the log and the mail doesn’t send.

I have tried both an email address on Google Apps that matches the domain of the web server, and an @gmail.com address (re granting access of course), but no luck. Can you help?

Serverinfo:
===========
OS: Linux ip-172-31-20-139 3.13.0-74-generic #118-Ubuntu SMP Thu Dec 17 22:52:10 UTC 2015 x86_64
PHP version: 5.5.9-1ubuntu4.14
WordPress version: 4.5.2
WordPress multisite: No
openssl: Available
allow_url_fopen: Enabled
stream_socket_client: Available
fsockopen: Available

Send Log:
============
Connection: opening to smtp.gmail.com:587, timeout=300, options=array ()
Connection: opened
SMTP -> get_lines(): $data is “”
SMTP -> get_lines(): $str is “220 smtp.gmail.com ESMTP 126sm52706365pfg.93 – gsmtp”
SERVER -> CLIENT: 220 smtp.gmail.com ESMTP 126sm52706365pfg.93 – gsmtp
CLIENT -> SERVER: EHLO grieflinepreprod.mjarmstrong.me
SMTP -> get_lines(): $data is “”
SMTP -> get_lines(): $str is “250-smtp.gmail.com at your service, [52.63.147.132]”
SMTP -> get_lines(): $data is “250-smtp.gmail.com at your service, [52.63.147.132]”
SMTP -> get_lines(): $str is “250-SIZE 35882577”
SMTP -> get_lines(): $data is “250-smtp.gmail.com at your service, [52.63.147.132]250-SIZE 35882577”
SMTP -> get_lines(): $str is “250-8BITMIME”
SMTP -> get_lines(): $data is “250-smtp.gmail.com at your service, [52.63.147.132]250-SIZE 35882577250-8BITMIME”
SMTP -> get_lines(): $str is “250-STARTTLS”
SMTP -> get_lines(): $data is “250-smtp.gmail.com at your service, [52.63.147.132]250-SIZE 35882577250-8BITMIME250-STARTTLS”
SMTP -> get_lines(): $str is “250-ENHANCEDSTATUSCODES”
SMTP -> get_lines(): $data is “250-smtp.gmail.com at your service, [52.63.147.132]250-SIZE 35882577250-8BITMIME250-STARTTLS250-ENHANCEDSTATUSCODES”
SMTP -> get_lines(): $str is “250-PIPELINING”
SMTP -> get_lines(): $data is “250-smtp.gmail.com at your service, [52.63.147.132]250-SIZE 35882577250-8BITMIME250-STARTTLS250-ENHANCEDSTATUSCODES250-PIPELINING”
SMTP -> get_lines(): $str is “250-CHUNKING”
SMTP -> get_lines(): $data is “250-smtp.gmail.com at your service, [52.63.147.132]250-SIZE 35882577250-8BITMIME250-STARTTLS250-ENHANCEDSTATUSCODES250-PIPELINING250-CHUNKING”
SMTP -> get_lines(): $str is “250 SMTPUTF8”
SERVER -> CLIENT: 250-smtp.gmail.com at your service, [52.63.147.132]250-SIZE 35882577250-8BITMIME250-STARTTLS250-ENHANCEDSTATUSCODES250-PIPELINING250-CHUNKING250 SMTPUTF8
CLIENT -> SERVER: STARTTLS
SMTP -> get_lines(): $data is “”
SMTP -> get_lines(): $str is “220 2.0.0 Ready to start TLS”
SERVER -> CLIENT: 220 2.0.0 Ready to start TLS
CLIENT -> SERVER: EHLO grieflinepreprod.mjarmstrong.me
SMTP -> get_lines(): $data is “”
SMTP -> get_lines(): $str is “250-smtp.gmail.com at your service, [52.63.147.132]”
SMTP -> get_lines(): $data is “250-smtp.gmail.com at your service, [52.63.147.132]”
SMTP -> get_lines(): $str is “250-SIZE 35882577”
SMTP -> get_lines(): $data is “250-smtp.gmail.com at your service, [52.63.147.132]250-SIZE 35882577”
SMTP -> get_lines(): $str is “250-8BITMIME”
SMTP -> get_lines(): $data is “250-smtp.gmail.com at your service, [52.63.147.132]250-SIZE 35882577250-8BITMIME”
SMTP -> get_lines(): $str is “250-AUTH LOGIN PLAIN XOAUTH2 PLAIN-CLIENTTOKEN OAUTHBEARER XOAUTH”
SMTP -> get_lines(): $data is “250-smtp.gmail.com at your service, [52.63.147.132]250-SIZE 35882577250-8BITMIME250-AUTH LOGIN PLAIN XOAUTH2 PLAIN-CLIENTTOKEN OAUTHBEARER XOAUTH”
SMTP -> get_lines(): $str is “250-ENHANCEDSTATUSCODES”
SMTP -> get_lines(): $data is “250-smtp.gmail.com at your service, [52.63.147.132]250-SIZE 35882577250-8BITMIME250-AUTH LOGIN PLAIN XOAUTH2 PLAIN-CLIENTTOKEN OAUTHBEARER XOAUTH250-ENHANCEDSTATUSCODES”
SMTP -> get_lines(): $str is “250-PIPELINING”
SMTP -> get_lines(): $data is “250-smtp.gmail.com at your service, [52.63.147.132]250-SIZE 35882577250-8BITMIME250-AUTH LOGIN PLAIN XOAUTH2 PLAIN-CLIENTTOKEN OAUTHBEARER XOAUTH250-ENHANCEDSTATUSCODES250-PIPELINING”
SMTP -> get_lines(): $str is “250-CHUNKING”
SMTP -> get_lines(): $data is “250-smtp.gmail.com at your service, [52.63.147.132]250-SIZE 35882577250-8BITMIME250-AUTH LOGIN PLAIN XOAUTH2 PLAIN-CLIENTTOKEN OAUTHBEARER XOAUTH250-ENHANCEDSTATUSCODES250-PIPELINING250-CHUNKING”
SMTP -> get_lines(): $str is “250 SMTPUTF8”
SERVER -> CLIENT: 250-smtp.gmail.com at your service, [52.63.147.132]250-SIZE 35882577250-8BITMIME250-AUTH LOGIN PLAIN XOAUTH2 PLAIN-CLIENTTOKEN OAUTHBEARER XOAUTH250-ENHANCEDSTATUSCODES250-PIPELINING250-CHUNKING250 SMTPUTF8
Auth method requested: XOAUTH2
Auth methods available on the server: LOGIN,PLAIN,XOAUTH2,PLAIN-CLIENTTOKEN,OAUTHBEARER,XOAUTH

https://ww.wp.xz.cn/plugins/gmail-smtp/