It seems your server configuration doesn’t support headers in .htaccess. Should

Hello Guys, I am writing to you from Peru, I have the following error message, I hope you can give me a cable, thanks:

It seems your server configuration doesn’t support headers in .htaccess. Should I fix this (install mod_headers) or disable the option “Enable direct redirection to existing converted images?” option. Otherwise the Vary: Accept header will not be added and this can lead to problems for users behind proxy servers (i.e. used in larger companies)