acsnaterse

This WordPress plugin blocks, by default, login attempts for the “admin” user. Because bots and hackers use automated login attempts on WordPress websites, specifically using the “admin” username, it’s a good practice to never use this username. This plugin will block all login attempts that try to use this username.
<h3>Features</h3>
<ul>
<li>Block “admin” user only</li>
<li>Block every user, but the usernames in your website.</li>
<li>Choose the URL you want to blocked users to be redirected to. We will <a href="https://www.youtube.com/watch?v=dQw4w9WgXcQ" rel="nofollow ugc">Rickroll</a> them by default. Of course.</li>
</ul>

Block user logins

Blocks every login attempt for the "admin" user, or every user, but the users in your install.

rajuru

SparkPost

The <a href="https://www.sparkpost.com/" rel="nofollow ugc">SparkPost</a> email delivery service offers best in class deliverability to ensure your mail hits the inbox, live analytics to review, track and optimize your email activities, as well as highest performance when you need it most: always.
When the SparkPost plugin is enabled, all outgoing email from your WordPress installation is sent through your SparkPost service. From within <a href="https://app.sparkpost.com/" rel="nofollow ugc">the SparkPost UI</a> or <a href="https://app.eu.sparkpost.com/" rel="nofollow ugc">SparkPost EU UI</a>, you can then watch your campaigns unfold live by tracking your engagement metrics, learn what your audience responds to and even integrate more deeply with your app using the SparkPost API.
Requirements 
– PHP 7.0 or later 
– WordPress 5.5 or later

Send all your email from WordPress through SparkPost, the most advanced email delivery service.

Block user logins vs SparkPost