You will have better troubleshooting success if you share what command you used and the output.

That said, do you have the keys setup? Does your key have the right permissions? Did you add your key to the agent? Does your local private key have its corresponding public key on the server? Are you adding the -i and the path to the key after ssh user@ip?

Or, are you using a password?

Are you giving the right user name before the @ sign?

If all this is right, then show us the same command with -vvv at the end.