After a succesful DietPi with Openssh server installation a putty ssh login gives following error:
Access denied
As I am inside a firewall on my own on the network, I am not concerned about security...for now

My /etc/ssh/sshd_config is the default/as installed config file.
Accept for following changes:
PermitRootLogin yes
PasswordAuthentication yes
usePAM no .. I changed this default because I got a PAM authentication failure with that enabled
I did useradd user1, passwd user1 .
The users login/password were tested successfully
Tried to ssh with putty and login as root and user1 with the same result: Access denied
journalctl -xe |grep ssh
Failed password for root from 192.168.1.100 port 500356 port 22 [preauth]
Same for user1
I telnet to my DietPi box with telnet 192.168.1.100 22 with response:
SSH-2.0-OpenSSH_7.9p1 Rasbian-10+deb10u2
So.. the firewall and network access is fine, ssh server service is running
Thanks in advance