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BugZero found this defect 403 days ago.
Connections to a Linux machine fail with the following errors: Authentication was partially successful, but server requires additional authentication with: 'password'. No suitable authentication method is supported. Supported methods: 'password'.
This error occurs when the remote Linux machine's SSH service /etc/ssh/sshd_config has been configured to require two or more authentication methods in sequence. For example, "AuthenticationMethods publickey,password" would require that all connections must provide first the publickey and then enter the account password. Veeam Backup & Replication supports SSH authentication using username and password or publickey, but it does not support the use of both in sequence.
Update the AuthenticationMethods setting within /etc/ssh/sshd_config so that it does not require more than one authentication method.
AuthenticationMethods details in sshd_config man page