Linxu SSH login appears Access Denied error solution

In fact, this problem is from the SCP. Use SCP to transfer backup files between two Linux servers. After entering the root password, the Permission denied, please try again. error appears. After modifying the target server root password with the Passwd command, the problem remains the same. Judging to judge, the problem remains.
Find a few solutions on the Internet: 1, /home permissions problem If /home only supports root access, then try /tmp, then use the mv command to transfer 2, /etc/ssh/sshd_config configuration problem Some people say This configuration file has been modified or optimized. Find the PermitRootLogin option inside, change no to yes, all methods have been tried, and even passwd, shadow permissions are invalid. Later, I re-established a user, granted root privileges, experimented, and succeeded! Since other accounts can succeed, why is root not? Look at putty again, found that connected to SSH, after entering the password also appeared Access Denied words. And the password is 100% correct. Finally found the solution, the original problem is still in the sshd_config, at the end of the file found an AllowUsers option, add root and then restart sshd. . . .
The code is as follows: /etc/init.d/sshd restart Let's take a look at the SSH connection and SCP command transfer. Already available.