I get this xhtml validation error for this code but I can see a href in all cases. What is wrong?
<ul>
<li><a href="http://www.facebook.com/spiros.doikas" target="_blank" rel="nofollow" /><img src="https://www.translatum.gr/forum/Themes/default/images/smifacebook.png" alt="spiros.doikas" /></a></li>
<li><a href="https://plus.google.com/102094522373850556729" target="_blank" rel="nofollow" /><img src="https://www.translatum.gr/forum/Themes/default/images/smigoogleplus.png" alt="102094522373850556729" /></a></li>
<li><a href="http://www.linkedin.com/in/doikas" target="_blank" rel="nofollow" /><img src="https://www.translatum.gr/forum/Themes/default/images/smilinkedin.png" alt="doikas" /></a></li>
<li><a href="http://www.twitter.com/greektranslator" target="_blank" rel="nofollow" /><img src="https://www.translatum.gr/forum/Themes/default/images/smitwitter.png" alt="greektranslator" /></a></li>
<li><a href="http://www.youtube.com/user/lavagraph" target="_blank" rel="nofollow" /><img src="https://www.translatum.gr/forum/Themes/default/images/smiyoutube.png" alt="lavagraph" /></a></li>
</ul>
Here is the page:
https://www.translatum.gr/forum/index.php?topic=454720.0
https://validator.w3.org/check?uri=https%3A%2F%2Fwww.translatum.gr%2Fforum%2Findex.php%3Ftopic%3D454720.0;accept=text%2Fhtml%2Capplication%2Fxhtml%2Bxml%2Capplication%2Fxml%3Bq%3D0.9%2Cimage%2Fwebp%2C%2A%2F%2A%3Bq%3D0.8;accept-language=en-US%2Cen%3Bq%3D0.8%2Cel%3Bq%3D0.6