Solution :
I had faced this message before. I had done lot of research on it. It is a bit tricky to fix this.
You must add a blowfish password to your phpMyAdmin's config file. You need to edit file at following path /etc/webapps/phpmyadmin/config.inc.php and after that you need to insert the any random blowfish "password" in below line
$cfg['blowfish_secret'] = ; /* YOU MUST FILL IN THIS FOR THE COOKIE AUTH! */
It should now look similar to this:
$cfg['blowfish_secret'] = 'qtdRoGmbc9{8IZr323xYcSN]0s)r$9b_JUnb{~Xz'; /* YOU MUST FILL IN THIS FOR THE COOKIE AUTH! */
This is with all assumes you have already correctly created your config file,
Then use below command to fix it.
cp config.sample.inc.php config.inc.php
Hope this solution will fix your issue.