Solve Forbidden You don't have permission to access /phpmyadmin/ on this server.

Edit your httpd.conf file as follows:

# nano /etc/httpd/conf/httpd.conf

Add the following lines here:

    Order allow,deny
    Allow from all

 # service httpd restart

If your problem is not solved then disable your SELinux.

and when got eror need  blowfish secret  just do this thing:
edit file config.inc.php in /usr/share/phpmyadmin
 nano/usr/share/phpmyadmin/config.inc.php

put your password

$cfg['blowfish_secret'] = ‘dfd3kjGj12dfT27665Z‘; /* YOU MUST FILL IN THIS FOR COOKIE AUTH!