Why Git Push Fails Even When SSH Is Set Up

• 2 min read

A common GitHub issue many developers face is this:

  • ssh -T git@github.com ✅ works

  • git push ❌ fails with Permission denied (publickey)

At first glance, this feels confusing. If SSH authentication works, why can’t Git push?

The answer lies in the SSH agent.

The Real Problem: SSH Agent Has No Keys Loaded

When you run:

ssh-add -l

and see no output, it means:

The SSH agent is running, but no SSH keys are loaded into it.

So even though:

  • Your SSH key exists on disk

  • Your SSH key is added to GitHub

  • Authentication can work in some cases

👉 git push has no key to use, and GitHub rejects the request.

Why ssh -T git@github.com Can Still Work

This is the confusing part.

  • ssh -T may try keys directly from disk

  • Your OS keychain may temporarily supply a key

  • But Git relies strictly on the SSH agent

So authentication appears fine, but authorization during push fails.

The Immediate Fix

Run these two commands:

$ eval "$(ssh-agent -s)" 

$ ssh-add ~/.ssh/id_ed25519

Verify:

ssh-add -l

You should now see your key listed.

After this:

git push

✅ Works.

Do You Have to Do This Every Time?

By default: yes, once per terminal session.

Each new terminal starts with an empty SSH agent.

Add this to ~/.bashrc or ~/.zshrc:

eval "$(ssh-agent -s)" > /dev/null ssh-add ~/.ssh/id_ed25519 2>/dev/null

Now:

  • Open a terminal

  • SSH key is automatically loaded

  • Git push works every time

Key Takeaway

SSH setup is not enough — the SSH agent must have your key loaded.

Most “mysterious” GitHub permission errors come down to this single missing step.

Once fixed, your Git workflow becomes seamless and predictable.