I newer version of xampp you may use another method first open your httpd-xampp.conf file and find the string "phpmyadmin" using ctrl+F command (Windows). and then replace this code
Alias /phpmyadmin "D:/server/phpMyAdmin/"
<Directory "D:/server/phpMyAdmin">
AllowOverride AuthConfig
Require local
ErrorDocument 403 /error/XAMPP_FORBIDDEN.html.var
</Directory>
with this
Alias /phpmyadmin "D:/server/phpMyAdmin/"
<Directory "D:/server/phpMyAdmin">
AllowOverride AuthConfig
Require all granted
ErrorDocument 403 /error/XAMPP_FORBIDDEN.html.var
</Directory>
Don't Forget to Restart your Xampp.