Campaign Template Save gives 403 Access Denied error

I'm running phplist 3.4.8 and am unable to save any Campaign Templates when I try to create or modify ones which were originally created with an earlier version of phplist (3.3.1).

When I try to save a campaign template I get:

Access to this resource on the server is denied!

For the following Minimalst Template the edit pages opens but if save is done with out any changes I get the 403 error.

Minimalst Template 

<div style="max-width:600px;background:#FFF;display:block;margin:0px auto;font-family: Arial,sans-serif;font-size:12px">
<p style="text-align:right"><a href="[FORWARDURL]">Forward this message</a></p>

<table cellpadding="20px" cellspacing="0px" style="border:2px solid #CCC; color:#333;" width="100%">

<p style="text-align:right">[FOOTER]</p>

I noticed if I removed the following line it saves successfully

<div style="max-width:600px;background:#FFF;display:block;margin:0px auto;font-family: Arial,sans-serif;font-size:12px">

Any ideas what is going on or how I can get further troubleshooting information?

I had html code examples in my post but they are being interpeted when published. Not sure how to post html code in this forum so it doesn’t get interpeted.

@halfmack use the toolbar code button </> when copying html.

It looks like anti-malware software is objecting to the content of the template, possibly because it looks like a complete html page. See this earlier topic Unable to save new Subscribe page

Followed up with my web hosting provider and mod_security was the issue. The disabled some of the mod_security rules and things are now working.

I tried the </> option but it still interperts the html code samples.

Thanks for your assitance.

@halfmack You need to highlight the text first then click the button

<b>some text in bold</b>

Ahh okay.Corrected original posting.