I tried all the methods that is needed to add root login without SSH keys but it was not successful. I configured sshd_config permitting root login and authorization of password. i cannot login with username and password. Appreciate your support on this.
I would like to connect GCP VMs using Putty without any SSH keys,using username and password.
What OS are you using? Sometimes inside /etc/ssh, apart from the ssh_config there is also another folder (i.e. sshd_config.d) that contains ssh setting. Most of the cases, the files inside this folder overwrite the primary ssh_config. Therefore even you already edited the primary ones, you still can’t connect.
Have you checked the folder as I previously suggested? Also just to be sure, you did a reload/restart to sshd service right? & password configuration via sudo passwd root?
DamianS suggestion is great, you need to debug the client SSH connection while trying to connect to the server. You can also do it from the inside of VM Terminal using ssh root@localhost -vvv