Content Encoding Error

[uanet]

I have interesting problem with this extension.

I receive Error in FireFox:

Content Encoding Error
The page you are trying to view cannot be shown because it uses an invalid or unsupported form of compression.
Please contact the website owners to inform them of this problem.";

Same error occur in Chrome too.

This error occur when loading page for first time. Not only the first page, for each page when loading for first time. After pressing browser reload button everything work OK. Problem is that, customers don't press "reload".

My Opencart version is 1.5.6 .
PHP version is: 5.4.4-14+deb7u14
Web server is: nginx/1.2.1
php_sapi_name: fpm-fcgi

Mozilla Page info tool show: Type: application/xhtml+xml.
When reload page, same tool show: Type: text/html.

Maybe error is in this lines:

foreach (headers_list() as $header) {
            if (preg_match('#^content-type:\s*text/html#i',$header)) {
                return true;
            }

I try with gzip compression on and off but problem is not here.

There is nothing in Opencart error log or in nginx error log.

[budgetneon]

Your theme is using a mime type of "application/xhtml+xml", so yes, that's causing the problem.

The cache doesn't currently support that.