Postman causing cron slowdown

The cron for my site is burdened with Postman requests that seem to go on much too long.

http://www.awesomescreenshot.com/image/1426457/d4c958bbdc67dab018dd934bef905fa4

http://www.awesomescreenshot.com/image/1426480/cb486200ee0b0529f686129700480bf7

This is causing all my site’s crons to get out of sync and not fire at all.

Any idea what can be done to mitigate?

OS: Linux 4.3.6-201.fc22.x86_64 #1 SMP Mon Feb 22 13:39:09 UTC 2016 x86_64
PHP: Linux 5.5.24 en_US.UTF-8
PHP Dependencies: iconv=Yes, spl_autoload=Yes, openssl=Yes, sockets=Yes, allow_url_fopen=Yes, mcrypt=Yes, zlib_encode=Yes
WordPress: 4.5.3 en_US UTF-8
WordPress Theme: Divi Child
WordPress Plugins: Native PHP Sessions for WordPress, Bloom, Child Theme Configurator, Divi Article Cards, Justuno Social Offers, Maje WC No PO Boxes, Postman SMTP, Redirection, Relevanssi, Simple Custom Post Order, TinyMCE Advanced, Tracking Link Generator, Abandoned Cart Lite for WooCommerce, WooCommerce Dynamic Pricing, WooCommerce Amazon Payments Advanced Gateway, WooCommerce AdWords Conversion Tracking, WooCommerce Google Analytics Integration, WooCommerce AdWords Dynamic Remarketing, WooCommerce PayPal Pro, WooCommerce Product Add-ons, WooCommerce Google Product Feed, WooCommerce Products Compare, WooCommerce Quick View, WooCommerce Subscribe to Newsletter, WooCommerce Tab Manager, WooCommerce Variation Swatches and Photos, WooCommerce, WooThemes Helper, Yoast SEO, WP Smush, T-HUB Component for WooCommerce
WordPress wp_mail Filter(s): wp_staticize_emoji_for_email
Postman: 1.7.2
Postman Sender Domain (Envelope|Message): norcrossmarine.com | norcrossmarine.com
Postman Prevent Message Sender Override (Email|Name): Yes | Yes
Postman Active Transport: SMTP (smtp:tls:plain://smtp.mandrillapp.com:587)
Postman Active Transport Status (Ready|Connected): Yes | Yes
Postman Deliveries (Success|Fail): 823 | 18

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