XF 2.0 Installing Tracking Pixels

[KindaBleh]

I'm trying to install a Facebook Tracking pixel that I want to show up on every page.
I searched the forum and found for previous versions of Xenforo, it was recommended to paste the code in the header of the PAGE_CONTAINER.
I tried that, but am getting an error that says "Oops! We ran into some problems." whenever I try to edit the PAGE_CONTAINER template.
The strange thing is, even if I try to just save the current version of this template, without editing anything, that error still shows up. But I can change other template files just fine.

Any ideas on why this might be happening?

 

[Mike]

That error is almost certainly caused by mod_security or something similar on your server blocking the request. Your host should be able to identify the rule and whitelist it.