 <p>In your code you have:</p> <pre><code>html "&lt;a href=" $ { link } "&gt;Activate your account on Kunega&lt;/a&gt;" </code></pre> <p>which I suppose should be either:</p> <pre><code>html "&lt;a href=\""+ link + "\"&gt;Activate your account on Kunega&lt;/a&gt;" </code></pre> <p>or </p> <pre><code>html "&lt;a href=\"${ link }\"&gt;Activate your account on Kunega&lt;/a&gt;" </code></pre> <p>otherwise you call a method <code>html</code> with params <code>"&lt;a href="</code>, <code>$</code>, <code>{ link }</code> (closure that returns "link") and <code>"&gt;Activate your account on Kunega&lt;/a&gt;"</code>.</p>