Set Headers for JSON in Apache proxy

Hello I try set header JSON in Apache proxy. I need this for test login in website. Below I put my apache config.

<VirtualHost *:80>
    ServerName zx.xxxxxxx.xxxxxx.fr

    ServerAdmin [email protected]

    AddDefaultCharset utf-8
    AddType 'application/json; charset=UTF-8' .json

    SSLProxyEngine On
    RequestHeader set Host "xxxxxxx.xxxxxx.fr"
    ProxyPreserveHost On
    ProxyPass / https://11.111.111.111/
    ProxyPassReverse / https://11.111.111.111/


    LogLevel warn
    ErrorLog /var/log/httpd/zx.xxxxxxx.xxxxxx.fr.log
    CustomLog /var/log/httpd/zx.xxxxxxx.xxxxxx.fr.log combined
</VirtualHost>

Please give me some advice where I do mistake.

Regards Mick