Well, we all have been there where we are supposed has learnt something useful every single day. I intend to keep going and learn something new from day to day.
After setting up the vsftp to use PAM as auth. Somehow having the following error appeared in tail -f /var/log/secure Sep 21 09:47:45 g-server vsftpd: PAM [error: /lib/security/pam_userdb.so: wrong ELF