phpMyAdmin not login

Upon entering the phpMyAdmin, I type the login and password, and after a while returns to ask for login and password.

On no account can access phpMyAdmin

You need to add Mysql user in CWP, or you can login using user root (password was shown up at the end of CWP installation), not recommend to login using root account.
I assume you understand the different of Mysql root account / SSH root account