Does your Cloud id turns white?
If not, that means that the CueCore3 cannot reach internet and connect to the cloud.
Or maybe you made a mistake in the cloud id.
you can test the connection of the CueCore to internet with the ntp server. Type this ip address: 216.239.35.8, if it turns white that means that your CueCore can reach the internet if it stays orange that means you have a network issue.