Permissions 0644 for 'LightsailDefaultKey-eu-central-1.pem' are too open. It is required that your private key files are NOT accessible by others. This private key will be ignored. code example
Example 1: Permissions 0644 for '/root/.ssh/id_rsa' are too open.
chmod 600 ~/.ssh/id_rsaExample 2: private key is too open
chmod 600 ~/.ssh/id_rsa