Ensure you have added your SSH key in your Gitlab account

Run the command ssh -v git@gitlab.blackswift.cloud (or -vvv) to see if there are any connectivity issues or errors.

Check to make sure that the correct SSH key is being used for the private repository. This key should be added to the ssh-agent, which is responsible for managing SSH keys.

To check if the correct SSH key is being used, run the command ssh-add -l. This will list all of the keys that are currently managed by the ssh-agent.

If the correct SSH key is not being used, it can be added to the ssh-agent using the command ssh-add /path/to/private_key.

If the issue is still not resolved, it is possible that there is a problem with the ssh-agent itself. To fix this, try running the command eval "$(ssh-agent -s)" to start a new ssh-agent and then add the correct SSH key using the ssh-add command from the previous step.

If the problem persists after trying these steps, it may be necessary to check the ssh configuration files (located in the ~/.ssh directory) for any issues or misconfigurations.

https://gitlab.blackswift.cloud/help/user/ssh.md

https://docs.github.com/en/authentication/connecting-to-github-with-ssh/generating-a-new-ssh-key-and-adding-it-to-the-ssh-agent

https://www.ssh.com/academy/ssh/agent

https://kb.iu.edu/d/aeww