SSH says "Permission denied (publickey)" or "server refused our key"

This almost always means the wrong key, username, or IP. Connect as root, using the private key that matches the public key you selected at instance creation, and the exact IP shown in the console:

ssh -i /path/to/private_key root@INSTANCE-IP

Add -vvv for detailed output. If it still fails, generate a new key pair and redeploy with the new key.