I suggest that you follow those steps:
Step 1: Check for existing SSH keys
$> ls -al ~/.ssh
Do you see any files named id_rsa and id_rsa.pub?
If yes go to Step 3
If no, you need to generate them
Step 2: Generate a new SSH key
$> ssh-keygen -t rsa -b 4096 -C "yourEmail"
Add your SSH key to the ssh-agent
$> eval "$(ssh-agent -s)"
$> ssh-add ~/.ssh/id_rsa
Step 3.1: Add the SSH key to your GIT account.
Get your public key
$> cat ~/.ssh/id_rsa.pub
Go to your GIT Account Settings (your profile picture in the upper right corner) -> Settings -> SSH and GPG keys -> New SSH key
Then paste the content of your public key into SSH keys
Step 3.2: Force SSH Client To Use Given Private Key
This is an alternative solution when you can't set keys on your Git account
$> sudo nano ~/.ssh/config
Then change this line
IdentityFile <yourPrivateKey>
Step 4: Clone the project
$> git clone [email protected]:xxx/xxx/git
~/.ssh/id_rsa.pubin your account profile (e.g. GitHub, BitBucket)?