Hello ,
It seems file /var/log/wtmp is missing. Please follow up below procedure.
1. check if there is /var/log/wtmp.
root@% ls -la /var/log/wtmp
2. If no such file, we will create it.
root@% touch /var/log/wtmp
root@% chmod 664 /var/log/wtmp
root@% chown root /var/log/wtmp
3. check it again.
root@% ls -la /var/log/wtmp .