SSH Permission denied (publickey)

1. About the error
2. Why do I see this error
3. Solution
4. Diagnose first
5. Make sure your key is on the server
6. Offer only the right key
7. Fix permissions on the server

#About the error

Connecting over SSH fails with:

Permission denied (publickey).

The server only accepts public-key authentication, and none of the keys your client presented matched an entry in the account's authorized_keys. A related variant, Too many authentication failures, means your client offered so many wrong keys that the server cut you off before reaching the right one.

#Why do I see this error

• Your public key isn't in the server's ~/.ssh/authorized_keys.
• The client is offering the wrong key, or every key in your agent.
• File permissions on the server's .ssh directory or authorized_keys are too open, so sshd ignores them.
• You're connecting as the wrong user.

#Solution

#Diagnose first

Verbose output shows exactly which keys are offered and how the server responds:

ssh -vvv user@your-server

#Make sure your key is on the server

The easiest way to install your public key is ssh-copy-id:

ssh-copy-id user@your-server

Or append it manually to ~/.ssh/authorized_keys on the server.

#Offer only the right key

If you have many keys, the agent offers them all and can trip "Too many authentication failures". Force a single key and ignore the agent:

ssh -o IdentitiesOnly=yes -i ~/.ssh/id_ed25519 user@your-server

Make it permanent in ~/.ssh/config:

Host your-server
    HostName your-server.example.com
    User deployer
    IdentityFile ~/.ssh/id_ed25519
    IdentitiesOnly yes

#Fix permissions on the server

sshd refuses keys if the files are world-writable. The .ssh directory must be 700 and authorized_keys must be 600, both owned by the account's user:

chmod 700 ~/.ssh
chmod 600 ~/.ssh/authorized_keys
chown -R $USER:$USER ~/.ssh

After fixing this, reconnect and the key should be accepted.