Post SMTP Mailer/Email Log的作者是Yehuda Hassine，目前有100,000+个有效安装。已经Tested with 5.4.1版本的wordpress。
LOOKING FOR GOOGLE ANALYTICS AIO PLUGIN?
If you used the good and old Google Analytics Dashboard For WP, I have forked the original plugin here:
THE ONLY SMTP PLUGIN WITH CHROME NOTIFICATIONS
Get notified if your emails are failing inside your Chrome browser. Download here
WORDPRESS MAIL SMTP PLUGIN
Post SMTP is a next-generation WP Mail SMTP plugin, that assists in the delivery of email generated by your WordPress site. Post SMTP is the first and only plugin to support the latest security standards. With OAuth 2.0, there is no need to store your email passsword in the WordPress database where it might be found.
The Connectivity Test and intelligent Setup Wizard scan your SMTP server to detect firewall blocks and eliminate configuration mistakes. The built-in Email Log is an invaluable resource for diagnosing problems with emails. Even hosts that block the standard SMTP ports, like GoDaddy or Bluehost, can’t stop your email as Post SMTP can deliver via HTTPS if it can’t use SMTP.
Post SMTP is not another WP Mail SMTP clone like WP Bank or Easy SMTP. It replaces the default WordPress SMTP library, PHPMailer, with the heavy-duty Zend_Mail. Never lose an email to PHP mail() again.
THE MOST FAST AND EASY
See how fast and easy to setup Post SMTP with Google/Gsuite or any SMTP service.
Easy-to-use, powerful Setup Wizard for perfect configuration
Commercial-grade Connectivity Tester to diagnose server issues
Log and resend all emails; see the exact cause of failed emails
Supports International alphabets, HTML Mail and MultiPart/Alternative
Supports forced recipients (cc, bcc, to) and custom email headers
SASL Support: Plain/Login/CRAM-MD5/XOAUTH2 authentication
Security Support: SMTPS and STARTTLS (SSL/TLS)
Copy configuration to other instances of Post
OAUTH 2.0 FEATURES
Supports the proprietary OAuth 2.0 implementations of Gmail, Hotmail and Yahoo
Fire-and-forget delivery continues even if your password changes
Gmail: By combining OAuth2 and the Gmail API, Post can deliver where other plugins can not
API (HTTPS) EMAIL SUPPORT
Gmail API for sending Gmail and Google Apps email (requires a Google account)
Often bloggers and small business owners don’t want to use third-party SMTP services. Well you can use your Gmail or G Suite account for SMTP emails.
Check the guide I wrote
Mandrill API for sending any email (requires a Mandrill account)
Mandrill is an email infrastructure service offered as an add-on for MailChimp that you can use to send personalized, one-to-one e-commerce emails, or automated transactional emails.
Mailgun API for sending any email (requires a Mailgun account)
Mailgun SMTP is a popular SMTP service provider that allows you to send large quantities of emails. They allow you to send your first 10,000 emails for free every month.
SendGrid API for sending any email (requires a SendGrid account and PHP 5.3)
SendGrid has a free SMTP plan that you can use to send up to 100 emails per day. With our native SendGrid SMTP integration, you can easily and securely set up SendGrid SMTP on your WordPress site.
Post SMTP needs translators! If you are a non-English speaker, please get involved!
Contact Form 7
Fast Secure Contact Form
Visual Forms Builder
Contact Form Builder
MyMail Newsletter by revaxarts
WP HTML Mail
.. and every other plugin that uses the WordPress API wp_mail to send mail!
WordPress 3.9 and PHP 5.6 with SPL and iconv
Memory: 750KiB per process at idle
Reliable mail delivery with custom email domains requires an SPF record
Reliable SMTP delivery requires credentials with an email service provider
OAuth 2.0 features require a Gmail, Hotmail or Yahoo mail OAuth 2.0 credentials
LOOKING FOR GOOGLE ANALYTICS PLUGIN?
If you used Google Analytics Dashboard For WP and you really hate the latest updates, I have forked the original plugin here:
Post SMTP (aka Postman SMTP) plugin was originally created by Jason Hendriks.
GRANT OAUTH PERMISSION ERROR MESSAGES
Please note that the Client ID and Client Secret fields are NOT for your username and password. They are for OAuth Credentials only.
ERROR AUTHENTICATING WITH THIS CLIENT ID. [ERROR EXECUTING WP_REMOTE_POST: THE USER HAS BLOCKED REQUESTS VIA HTTP.]
Your WordPress site is configured with WP_HTTP_BLOCK_EXTERNAL to prevent outbound connections. Add a whitelist rule to wp-config.php:
define(‘WP_ACCESSIBLE_HOSTS’, ‘www.googleapis.com, login.live.com, api.login.yahoo.com’);
ERROR AUTHENTICATING WITH THIS CLIENT ID. [ERROR EXECUTING WP_REMOTE_POST: FAILED TO CONNECT TO XXXX]
There is a firewall on port 443 between you and the OAuth2 server. Open up the port for outbound connections.
You did not enter the Redirect URI correctly, watch the instructional video
You used an IP address instead of a domain name (not allowed)
ERROR: INVALID_CLIENT … NO SUPPORT EMAIL
You’ve forgotten to choose an email address in the consent screen.
SMTP ERROR MESSAGES
COMMUNICATION ERROR  – MAKE SURE THE ENVELOPE FROM EMAIL IS THE SAME ACCOUNT USED TO CREATE THE CLIENT ID.
This is almost always caused by being logged in to Google/Microsoft/Yahoo with a different user than the one Post is configured to send mail with. Logout and try again with the correct user
Login to Webmail and see if there is an “Unusual Activity” warning waiting for your attention
COULD NOT OPEN SOCKET
Your host may have installed a firewall between you and the server. Ask them to open the ports.
Your may have tried to (incorrectly) use SSL over port 587. Check your encryption and port settings.
OPERATION TIMED OUT
Your host may have poor connectivity to the mail server. Try doubling the Read Timeout.
Your host may have installed a firewall (DROP packets) between you and the server. Ask them to open the ports.
Your may have tried to (incorrectly) use TLS over port 465. Check your encryption and port settings.
Your host has likely installed a firewall (REJECT packets) between you and the server. Ask them to open the ports.
503 BAD SEQUENCE OF COMMANDS
You configured TLS security when you should have selected no security.
XOAUTH2 AUTHENTICATION MECHANISM NOT SUPPORTED
You may be on a Virtual Private Server that is playing havoc with your communications. Jump ship.
MAIL ENDS UP IN THE SPAM FOLDER
To avoid being flagged as spam, you need to prove your email isn’t forged. On a custom domain, its up to YOU to set that up:
Ensure you are using the correct SMTP server with authentication – the correct SMTP server is the one defined by your email service’s SPF record
If you use a custom domain name for email, add an SPF record to your DNS zone file. The SPF is specific to your email provider, for example Google
If you use a custom domain name for email, add a DKIM record to your DNS zone file and upload your Domain Key (a digital signature) to, for example Google