 <p>I have finally found my own answer again. Basically, <strong>it came down to restart intellij</strong> and the plugin will show under plugins. For some reason while doing "Grails/Synchronize Grails Settings" was not making the plugin show up.</p> <p>So to successfully install the gails mail plugin do as follows</p> <ol> <li>Add <strong>activation1-1.jar</strong> and <strong>mail.jar</strong> to your lib folder</li> <li>In <strong>BuildConfig.groovy</strong> uncomment mavenCenral()</li> <li>Run grails command: <strong>grails install-plugin mail</strong></li> <li>In IntelliJ click on <strong>Apply Grails Changes to IDEA project structure</strong> if asked in the<br> yellow popup</li> <li>If IntelliJ still does not recognize the plugin do <strong>Grails/Synchronize Grails</strong> either by right clicking on "Plugins" or in the project name</li> <li>If IntelliJ still does not recognize the plugin, restart IntelliJ do a <strong>Grails/Synchronize Grails</strong>.</li> <li>The plugin should be correctly installed and ready to use.</li> </ol>