It is misterious thing as in my .htaccess file it is included new code.
Header set Content-Encoding gzip
I do not quite understand why I get this error.
Any advise available on it?
.htaccess Update Concerning Setting the Content-Encoding Header
Since version 4.2.9
Before 4.2.9 the default htaccess.txt file contained erroneous code for appending the "Content-Encoding" HTTP header. This could result in double encoding errors when Joomla is installed in a subdirectory and both this directory and its parent directory contain an .htaccess file with this code. You should manually apply the necessary changes to any existing .htaccess file, as this file can not be updated automatically.
The old code:
Header append Content-Encoding gzip
The new code:
Header set Content-Encoding gzip