Fatal error: Allowed memory size of 67108864 bytes exhausted

Hi! I’m receiving this error when people try to place in order through woocommerce…the order goes through but the email does not and I get the below error message.

Also, here is a link to the site in case you need it: http://www.heatherlindemenn.com/

Fatal error: Allowed memory size of 67108864 bytes exhausted (tried to allocate 8092 bytes) in /home/heatherl/public_html/wp-content/plugins/postman-smtp/Postman/Postman-Mail/Zend-1.12.10/Mime.php on line 470

This is what comes up when I run the connectivity test:
Summary:

✅ 🔒 Port 443 can be used to send Gmail with the Gmail API.
✅ 🔒 Port 25 can be used for SMTP to smtp.gmail.com.
❌ No outbound route between this site and the Internet on Port 587.
❌ No outbound route between this site and the Internet on Port 465.

DIAGNOSTIC INFO:
OS: Linux p3plcpnl0459.prod.phx3.secureserver.net 2.6.32-531.29.2.lve1.3.11.1.el6.x86_64 #1 SMP Thu Dec 18 06:49:17 EST 2014 x86_64
HTTP User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/43.0.2357.134 Safari/537.36
Platform: PHP Linux 5.4.37 / 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: Divi
WordPress Plugins: ManageWP – Worker, Better Analytics, Column Shortcodes, Contact Form 7, Elegant Themes Updater, Image Widget, Instagram Feed, Instagram for WordPress, Limit Login Attempts, Limit Login Attempts, Monarch Plugin, PopupAlly Pro, Postman SMTP, Go Daddy Quick Setup, Ultimate Pinterest Display Widget, WooCommerce, WordPress SEO, WP All Import, WP Editor, WP Google Fonts, YITH WooCommerce Tab Manager
Postman Version: 1.6.23
Postman Sender Domain (Envelope|Message): heatherlindemenn.com|heatherlindemenn.com
Postman Prevent Message Sender Override (Email|Name): No|No
Postman Transport URI: gmail_api:https:oauth2://www.googleapis.com:443
Postman Transport Status (Configured|Ready|Connected): Yes|Yes|Yes
Postman Deliveries (Success|Fail): 19|4
Postman Bind (Success|Fail|Path): Yes|No|/home/heatherl/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

Thank you for your time and help!

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