File config location :
/opt/lampp/etc/extra/httpd-xampp.conf

to enable :

# since XAMPP 1.4.3

<Directory "/opt/lampp/phpmyadmin">

    AllowOverride AuthConfig limit

    Require local

    Deny from All

#   Require all granted

#   Allow from all

    ErrorDocument 403 /error/XAMPP_FORBIDDEN.html.var

</Directory>


uncommand Require all granted & Allow from all

than

command Require local & Allow from all


Restart after edit config :

/opt/lampp/./lampp restart