Xserver VPS Permission denied (publickey) | Why You Can’t Connect After Registering SSH Keys

You registered your SSH public key in Xserver VPS, but you still can’t log in.

Permission denied (publickey)

The IP, username, and port seem correct, yet the connection fails.

This is a very common initial configuration mistake with Xserver VPS. The conclusion is simple: even if the SSH key is registered in the panel, it is not enabled on the OS level.

Conclusion: “Key Registration” Does Not Mean “SSH Ready”

In Xserver VPS, it is easy to assume:

• I registered the SSH public key in the control panel.
• Therefore, I can connect via SSH.

This is incorrect.

Why “Permission denied (publickey)” Occurs

When this error appears, SSH itself is usually not broken. The problem is a discrepancy:

• Control Panel: SSH key is registered.
• Server Internal: authorized_keys is not correctly configured.

In other words, “The key exists, but it is not being used.”

Common Misunderstandings with Xserver VPS

1. Thinking Registration is Enough

The SSH key registration in the Xserver VPS control panel does not automatically complete the user configuration inside the OS. This is especially true in the following cases:

• Immediately after VPS re-installation.
• When creating a user later.

2. Confusing Public and Private Keys

ssh-rsa XXXXXXXXXX

This is a Public Key.

To connect via SSH, you need:

• Client side: Private Key
• Server side: Corresponding Public Key

Even if the public key is registered, if the private key does not match, you will get Permission denied (publickey).

3. Ignoring Permissions

In Xserver VPS (and Linux in general), if any of the following are incorrect, SSH will fail immediately:

• .ssh directory: 700
• authorized_keys: 600
• Owner: The target user

If even one permission bit is off, SSH will mercilessly reject the connection.

Correct Solution

Configure the OS Side with Root Privileges

You must configure this inside the server, not just in the control panel.

mkdir -p /home/USER/.ssh
chmod 700 /home/USER/.ssh

echo "ssh-rsa XXXXXXXXX" >> /home/USER/.ssh/authorized_keys

chmod 600 /home/USER/.ssh/authorized_keys
chown -R USER:USER /home/USER/.ssh

Only then are the conditions met:

1. SSH
2. Public Key Authentication
3. User Connection

What to Check If It Still Fails

• Does the private key actually correspond to the public key?
• Are there any line breaks or missing characters in the key file?
• Is public key authentication disabled in sshd_config?

Mismatched key pairs are a very common cause.

Official Documentation Note

The Xserver VPS manual officially states that OS-side configuration is required after registering SSH keys.

Setting up Key Authentication for an Active Server
…
4. Registering the Public Key
Register the copied public key into the server’s SSH public key management file.

Source: SSH Key – Xserver VPS Manual

The correct understanding is not “I registered it but it doesn’t work,” but “It won’t work just by registering it.”

Summary | The Truth About Xserver VPS Permission denied (publickey)

If you see Permission denied (publickey) on Xserver VPS, the cause is likely one of the following:

In SSH troubleshooting, isolation is more important than configuration. First, verify “Is the key actually being used by the OS?”

Image Source: Xserver VPS Manual – SSH Key