Found it by grep command
in files
/www/server/panel/class_v2/one_key_wp_v2.py
/www/server/panel/class_v2/flask_compress_v2.py
/www/server/panel/webserver/tpls/webserver_ssl.conf
/www/server/panel/webserver/conf/webserver.conf
/www/server/panel/class/flask_compress.py
/www/server/panel/class/one_key_wp.py
Comment lines having "x-frame-options"
And it works after panel restart