# Error: Key already in use

This error occurs when you try to add a key that's already been added to another account or repository.

## Finding where the key has been used

To determine where the key has already been used, open a terminal and type the `ssh` command. Use the `-i` flag to provide the path to the key you want to check:

```shell
$ ssh -T -ai ~/.ssh/id_rsa git@HOSTNAME
# Connect to your GitHub Enterprise Server instance using a specific ssh key
> Hi USERNAME! You've successfully authenticated, but GitHub does not
> provide shell access.
```

The *username* in the response is the account on your GitHub Enterprise Server instance that the key is currently attached to. If the response looks something like "username/repo", the key has been attached to a repository as a [*deploy key*](/en/enterprise-server@3.22/authentication/connecting-to-github-with-ssh/managing-deploy-keys#deploy-keys).

To force SSH to use only the key provided on the command line, use `-o` to add the `IdentitiesOnly=yes` option:

```shell
ssh -v -o "IdentitiesOnly=yes" -i ~/.ssh/id_rsa git@HOSTNAME
```

## Fixing the issue

To resolve the issue, first remove the key from the other account or repository and then [add it to your account](/en/enterprise-server@3.22/authentication/connecting-to-github-with-ssh/adding-a-new-ssh-key-to-your-github-account).

If you don't have permissions to transfer the key, and can't contact a user who does, remove the keypair and [generate a brand new one](/en/enterprise-server@3.22/authentication/connecting-to-github-with-ssh/generating-a-new-ssh-key-and-adding-it-to-the-ssh-agent).

## Deploy keys

Once a key has been attached to one repository as a deploy key, it cannot be used on another repository. If you're running into this error while setting up deploy keys, see [Managing deploy keys](/en/enterprise-server@3.22/authentication/connecting-to-github-with-ssh/managing-deploy-keys).