Cannot clone git repo via SSH

I am getting below error while trying to clone repository.

$ git clone git@gitlab.com:VenkateshDevam/CIDEMO.git
Cloning into ‘CIDEMO’…
The authenticity of host ‘gitlab.com (52.167.219.168)’ can’t be established.
ECDSA key fingerprint is SHA256:HbW3g8zUjNSksFbqTiUWPWg2Bq1x8xdGUrliXFzSnUw.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added ‘gitlab.com,52.167.219.168’ (ECDSA) to the list of known hosts.
git@gitlab.com: Permission denied (publickey).
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

I have the same problem, my public projects cannot be cloned via ssh.