Html tags and php tags are not parsed properly

Html tags and php tags are not parsed properly,

For ex, check out this link https://www.lessons99.com/quick-reference-php.html

In this link, <?php tag is displayed as <?php

Is there any setting that will correct this, FYI, I have done any changes in the setting, using the same default setting which comes when you activate the plugin.

https://www.ads-software.com/plugins/crayon-syntax-highlighter/