Funny problem afte reset mysql root password

Followed this link for root password reset,

https://help.ubuntu.com/community/MysqlPasswordReset

However, hit below funny error

user:~/workdir/mysqlbak/5.6shrink$ sudo /etc/init.d/mysql start
 * Starting MySQL database server mysqld X11 connection rejected because of wrong authentication.
No directory, logging in with HOME=/
                                                                                                                         [ OK ]
 * Checking for tables which need an upgrade, are corrupt or were
not closed cleanly.


Googled , but no much can help.

Tried my luck to reboot the Ubuntu server, and it seems working fine now.