Permission denied (publickey) means the SSH server rejected public-key authentication; it does not, by itself, mean your key file is corrupt. First verify the host and login name, then use verbose SSH output to see which key your client found and offered. That evidence tells you whether to check the key path or agent, key registration, local permissions, or server-side access.
What the error means—and what to check first
GitHub Docs explains: “A "Permission denied" error means that the server rejected your connection.” The message identifies an authentication failure, but not its cause. GitLab also documents several possible causes, so generating a new key immediately can miss a username, agent, or authorization problem.
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- Confirm the destination and account. Check the hostname and intended login name. For Git operations on GitHub, the SSH username is
git, so the destination is[email protected]—not your GitHub profile username. Other servers use their own account names. - Inspect the client’s key selection. Run the appropriate verbose command below and look for identity files and messages indicating that a key was offered.
- Check how that key is being supplied. Confirm the intended key is available in the current
ssh-agentsession, or explicitly select it with-i. - Verify authorization. Match the public key or its fingerprint to the destination account or server authorization.
- Check local permissions and remaining access rules. A private key the client cannot read, an unsupported key type, missing repository access, or server policy can still prevent login.
Use verbose output to locate the failure
GitHub
For a GitHub SSH connection, run:
ssh -vT [email protected]Read the output for identity-file discovery and key offers. If no intended identity is found or offered, investigate the path, filename, and agent. If the client offers a key but authentication fails, verify that the matching public key is registered to the intended GitHub account and that you are connecting to the right host.
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GitLab
For GitLab, substitute your GitLab instance’s hostname in this command:
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ssh -Tvvv [email protected]Look for the same distinction: no intended key offered points toward client-side selection or agent state; an offered but rejected key points toward registration, account, key support, or server authorization. GitLab’s example hostname is a placeholder for your instance, not a universal GitLab address.
If SSH finds no key or offers the wrong one
Check the agent in the session that fails
For the GitHub troubleshooting example, list keys loaded in the current agent with:
ssh-add -l -E sha256If the expected key is not listed, the agent may not have it loaded in that terminal or session. GitLab likewise identifies agent state as a possible cause when a connection works in one session but not another.
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Select a non-default key explicitly
If your private key is not at the default path or has a non-default filename, test with:
ssh -i ~/.ssh/KEY-FILE git@HOSTNAMEReplace KEY-FILE and HOSTNAME with the actual private-key filename and destination. For GitHub, retain [email protected] as the destination. If this works while the ordinary command fails, the issue is likely which identity SSH selects by default.
If a key is offered but rejected
Match the public key to the intended account or server
The private key on your computer must correspond to a public key authorized at the destination. Compare the public key or fingerprint for the identity shown in verbose output with the key registered to the hosting account. On a self-managed or regular SSH server, check the server-side authorized-key configuration for the intended operating-system account; there may be no hosting-account key page.
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Confirm the username and the kind of access
An SSH key can authenticate an account without granting access to every repository or action. For GitHub Git operations, use the platform’s git SSH username. On other systems, use the server’s correct login account. If SSH authentication succeeds but a repository operation is denied, check account membership or deploy-key access rather than treating it as the same public-key authentication failure.
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If the intended key is offered and registered, the destination may not support its type or may reject it under local policy. GitLab notes that ED25519 keys can be incompatible with some FIPS systems. A regular server may also impose its own SSH configuration or account-authorization rules; ask its administrator to verify those settings when you cannot inspect them yourself.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Check local key and directory permissions
GitLab’s documented permission checks specify mode 600 for the private key and 700 for the .ssh directory. On a Unix-like system, check or set them with:
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chmod 600 ~/.ssh/KEY-FILE
chmod 700 ~/.sshUse the actual private-key filename in place of KEY-FILE. These permissions address local access to the key; they do not register it with the remote account or grant repository rights.
Choose the next check from the evidence
| Verbose output or symptom | Next check |
|---|---|
| Identity file is absent, or no key is offered | Confirm the key path and filename, inspect the agent in this session, and try an explicit -i path. |
| A key is offered but authentication is rejected | Compare its public key or fingerprint with the destination’s authorized key; verify host, account, key support, and server policy. |
| GitHub Git connection uses a personal username | Retry with the GitHub-specific SSH username git. |
| GitLab works in one session but fails in another | Check whether the failing session’s agent has the intended key and verify local permissions. |
| Key is registered, but a repository action is denied | Check account or deploy-key access to that repository; authentication and repository authorization are separate checks. |
Keep this error distinct from other SSH failures
Permission denied (publickey) is a public-key authentication rejection. It is not the same as a host-key verification warning, DNS resolution failure, a blocked network connection, or a repository authorization error after authentication. GitHub’s troubleshooting index treats these as separate problems; use the message and the point of failure to choose the relevant branch.
Do not make sudo a routine fix for GitHub pushes. GitHub warns that a key created without elevated privileges may not be the key used by sudo git push; changing privilege context can therefore select a different identity rather than fix authentication.
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