Viktor Szépe

Enables users with <code>list_users</code> capability (Editors and Administrators) 
to send plain text message to any user in an email.
There is a new action “Send message” provided on the Users admin page 
for each user.

Send message

Send an email (subject and text message) to WordPress users.

Using SMTP protocol to transfer emails ensures solid operations. 
It is very easy to set up SMTP. You can find the settings for this plugin at the bottom of WordPress admin menu Options / General.
You should get your SMTP settings from your ISP, hosting provider, webmaster, email provider etc.
Using every option SMTP URI formally looks like this:
<pre><code>smtpTLS://USERNAME:PASSWORD@HOST:PORT
</code></pre>
Thus encryption type and <code>://</code> and user name and <code>:</code> and password and <code>@</code> and mail server name and <code>:</code> and port number. 
All except encryption type and mail server (host name) are optional.
SMTP encryption types are as follows:
<ul>
<li>For encrypted connection (STARTTLS on submission port) start your SMTP URI with <code>smtpTLS://</code> – the default port is 587.</li>
<li>For fully SSL encrypted connection (SMTPS) start it with <code>smtps://</code> – the default port is 465.</li>
<li>For unencrypted connection (plain SMTP) start it with <code>smtp://</code> – the default port is 25. This is not recommended for non-local servers.</li>
</ul>
WARNING! Use <a href="http://meyerweb.com/eric/tools/dencoder/" rel="nofollow ugc">URL-encoded</a> strings.
You can find the settings for this plugin at the bottom of WordPress admin Options / General.
You may define your SMTP URI also in <code>wp-config.php</code>:
<pre><code>define( 'SMTP_URI', 'smtpTLS://USERNAME:PASSWORD@HOST:PORT' );
</code></pre>
To set <code>From:</code> name and <code>From:</code> address use 
<a href="https://wordpress.org/plugins/wp-mailfrom-ii/" rel="ugc">WP Mail From II plugin</a>.
<h4>SMTP error logging</h4>
SMTP communication errors are logged in PHP error.log and – if 
<a href="https://wordpress.org/plugins/sucuri-scanner/" rel="ugc">Sucuri Scanner</a> 
plugin is available – are sent to Sucuri and can be viewed in its Alert Logs panel.
<h4>Adding automatic Bcc: address</h4>
An automatic Bcc: address can be set by adding path to SMTP URI: <code>/admin_email</code>.
<h4>SMTP debugging</h4>
Add query string to SMTP URI: <code>?debug</code>.
Debug level can be set by adding a value: <code>?debug=4</code>, possible values: 0,1,2,4
<h4>TODO</h4>
<ul>
<li>Option to skip newsletters: ALO Newsletter, Newsletter, Mailpoet.</li>
<li>Video on installing and setting up this plugin.</li>
<li>Remove <code>smtp_uri</code> option on uninstallation (I hope you won’t uninstall it)</li>
</ul>
<h4>Usage examples</h4>
Unauthenticated local SMTP server on port 25
<pre><code>smtp://localhost
</code></pre>
Unauthenticated local SMTP server on submission port
<pre><code>smtpTLS://localhost
</code></pre>
Authenticated connection to localhost on port 25
<pre><code>smtp://john.doe:Secretpwd1@localhost
</code></pre>
“@” sign in the username, a Gmail example
<pre><code>smtps://your.address%40gmail.com:Gmail_password@smtp.gmail.com
</code></pre>
Sendgrid example
<pre><code>smtpTLS://CREDENTIAL-USERNAME:PASSWORD@smtp.sendgrid.net
</code></pre>
Mandrill example
<pre><code>smtpTLS://REGISTERED%40EMAIL:API-KEY@smtp.mandrillapp.com
</code></pre>
Unauthenticated SMTP server on a custom port
<pre><code>smtpTLS://mail.server.net:2525
</code></pre>
Development goes on on <a href="https://github.com/szepeviktor/smtp-uri" rel="nofollow ugc">GitHub</a>.

SMTP URI and logging

SMTP settings for WordPress and error logging.

Send message vs SMTP URI and logging