Error installing/removing mail

It’s my first time that I encountered this error. I was installing mail server on my VPS as root but then it suddenly stopped. So I tried to remove mail by typing ee stack purge --mail. It’s not showing any error so I check the logs and here’s what I found.

 2015-12-02 00:21:49,055 (DEBUG) ee : ['/usr/local/bin/ee', 'stack', 'purge', '--mail']
2015-12-02 00:21:49,055 (DEBUG) ee : collecting arguments/commands for <ee.cli.controllers.base.EEBaseController object at 0x7fd7a34c32b0>
2015-12-02 00:21:49,058 (DEBUG) ee : collecting arguments/commands for <ee.cli.plugins.stack.EEStackController object at 0x7fd7a34c39e8>
2015-12-02 00:21:49,059 (DEBUG) ee : collecting arguments/commands for <ee.cli.plugins.stack_services.EEStackStatusController object at 0x7fd7a34c3be0>
2015-12-02 00:21:49,063 (INFO) ee : Initializing EasyEngine Database
2015-12-02 00:21:49,066 (DEBUG) ee : Removing mail server packages
2015-12-02 00:21:49,067 (DEBUG) ee : Running command: mysqladmin ping
2015-12-02 00:21:49,078 (DEBUG) ee : (1045, "#28000Access denied for user 'root'@'localhost' (using password: YES)")

I tried to login on mysql using root but it’s working well. I also checked my .my.cnf file, info is correct. Any ideas? Sorry for my bad english.