CentOS 6.5 user login problem

Hi,

I am having two users in my CentOS installation

root user1 (name changed)

user1 is having root privilege also

Problem is, while I was working in Putty with user1 login, my PC had a power failure… 30 mins later when I got the power back on, I found user1 was having access denied when trying to login.

I logged in via root and I checked with command

who

and found user1 still login with my previous IP (my ISP gives dynamic IP). So I ran command

skill -KILL -u user1

I checked and found that user is logout…

Since then still I cant login to that user… I changed its password via

passwd user1

Even with that new password also, user1 cant be logged in…

Then I checked log file and I found following error

User user1 from xxx.xxx...xxxx not allowed because not listed in AllowUsers

What can I do ?

Thanks.