cannot log into phpmyadmin

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http://forums.cpanel.net – I was supposed to deploy a new website with new database in place of my client's old website. Client gave me the cpanel username and password. I'm able to access the cpanel and use file manager and create mysql database and users. I was also able to log into phpmyadmin for once. I tried to import the zip file but gave me some error. After some time the session seem to expire and phpmyadmin asked me to re enter the user name and passsword again. But this time it refused to log me into. I tried creating a new mysql user name and password and added it to the database and tried to log in using it (HowTos)