The plugin works great on PHP v5.4 and v5.5.
For PHP v7.0.7 does not send e-mails.
I can send more data according to an instruction, or share the site for testing.
Session Transcript:
220 cloudserver023946.home.net.pl ESMTP IdeaSmtpServer v0.80.2 ready.
EHLO localhost
HELO localhost
250-cloudserver023946.home.net.pl Hello edl.pl [88.198.69.134], pleased to meet you
250-PIPELINING
250-ENHANCEDSTATUSCODES
250-SIZE
250-8BITMIME
250-AUTH PLAIN LOGIN
250-AUTH=PLAIN LOGIN
250 HELP
AUTH LOGIN
250 cloudserver023946.home.net.pl Hello edl.pl [88.198.69.134], pleased to meet you
OS: Linux server.edl.pl 3.2.71-grsec #1 SMP Tue Sep 1 11:53:52 CEST 2015 x86_64
PHP: Linux 7.0.7 C
PHP Dependencies: iconv=Yes, spl_autoload=Yes, openssl=Yes, sockets=Yes, allow_url_fopen=Yes, mcrypt=Yes, zlib_encode=Yes
WordPress: 4.5.2 pl_PL UTF-8
WordPress Theme: <SECRET>
WordPress Plugins: <SECRET>
WordPress wp_mail Filter(s): wp_staticize_emoji_for_email
WordPress phpmailer_init Action(s): wpcf7_phpmailer_init
Postman: 1.7.2
Postman Sender Domain (Envelope|Message): <SECRET> | <SECRET>
Postman Prevent Message Sender Override (Email|Name): No | No
Postman Active Transport: SMTP (smtps:login://<SECRET>.home.pl:465)
Postman Active Transport Status (Ready|Connected): Yes | Yes
Postman Deliveries (Success|Fail): 0 | 0
Postman Email Log (Enabled|Limit|Transcript Size): No | 250 | 128