Weird bug: WordPress auto convert PHP to HTML code

Dear all,

I just install a new Centos server with Ngnix and php-fpm.

Now, I am develop a template with my site at: bloggeritems.com
But a weird error is when I code like below:

<div class="blog-info">
				<?php $fname = 'Blogger Items'; ?>

				<?php if ( is_archive() ) : ?>
					<h1 class="site-title"><?echo $fname;?></h1>
				<?php else : ?>
					<h2 class="site-title"><?echo $fname?></h2>
				<?php endif; ?>

				<p class="site-description"><?php bloginfo( 'description' ); ?></p>
			</div>

The output result will like below:

<div class="blog-info">

									<h2 class="site-title"><!--?echo $fname?--></h2>

				<p class="site-description">Blogger and Blogspot Organization created amazing templates, widget, guide, tips, discussions and all free for you.</p>
			</div>

Mean <?echo $fname;?> in PHP will become <!--?echo $fname?--> in HTML
This is WP bug or I am a noob?

Appreciate all helps.

Best regards,
Tien Nguyen