How to fix SSH error: Could not open a connection to your authentication agent

The problem

Recently, I was trying to add a SSH key to the ssh-agent. So, I ran the following command:

ssh-add ~/.ssh/<key_name>

This resulted in the following error:

Could not open a connection to your authentication agent.

The solution

The error message is pretty clear. Since a connection to the ssh-agent could not be opened, first let’s check if the ssh-agent is running or not.

ps -e | grep [s]sh-agent

If the ssh-agent is not running, you will not see any output. This is exactly what happened in my case. So, the solution is simple: you need to start the ssh-agent.

You just need to run the following command to start the ssh-agent.

eval "$(ssh-agent -s)"

This should result in an output similar to the following.

Agent pid 59566

Now, you can try addding an SSH key to the ssh-agent.

ssh-add ~/.ssh/<key_name>

In my case, the key was added successfully.

Identity added: /home/user/.ssh/<key_name> (/home/user/.ssh/<key_name>)

Conclusion

To fix the ssh error: Could not open a connection to your authentication agent, you just need to start the ssh-agent.