Getting a "Permission Denied (publickey)"

If you see a "Permission denied (publickey)" error when trying to SSH using a key, here are some common problems to look for:

Check Key Permissions: Make sure your private key file has secure permissions. Set the permissions to 600.
```
 chmod 600 /path/to/private-key.pem
```
Check Key Format: Be sure your private key has the right format. SSH keys usually use OpenSSH format. If your key was made with a different tool, you might need to change it. To change a PuTTY private key (.ppk) to OpenSSH format, use this command:
```
 puttygen private-key.ppk -O private-openssh -o private-key.pem
```
Check SSH Agent: If you're using an SSH agent to manage your keys, ensure that the key is added to the agent using the ssh-add command:
```
 ssh-add /path/to/private-key.pem
```
Check Authorized Keys on Server: Make sure your public key is in the ~/.ssh/authorized_keys file on the remote server. You can add it yourself or use the ssh-copy-id command:
```
 ssh-copy-id -i /path/to/public-key.pub username@remote-server-ip
```
Replace /path/to/public-key.pub with the path to your public key file.
Check Server Configuration: Be sure the SSH server on the remote computer is set up to allow key-based authentication. Look at the sshd_config file on the server:
```
 sudo nano /etc/ssh/sshd_config
```
Ensure that the following lines are present and not commented out:
```
 PubkeyAuthentication yes
 AuthorizedKeysFile  .ssh/authorized_keys
```
Restart the SSH service after making changes:
```
 sudo service ssh restart
```
Check User Home Directory Permissions:Make sure the user's home directory on the remote server has the right permissions. It shouldn't be writable by the group or everyone:
```
 chmod 700 /home/username
```

After following these steps, try connecting again. If you still have problems, using the verbose mode (-v option) can give more information about the authentication process:

ssh -v -i /path/to/private-key.pem username@remote-server-ip

Check the output for any error messages that could help you find the issue.

Getting a "Permission Denied (publickey)" error while trying to SSH with a key

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