You should probably ask Apollo for help.

The original server of the challenge didn't match the attachment, so we released one that does: oracle2.2020.ctfcompetition.com If you want to connect to the old server, it's available at oracle.2020.ctfcompetition.com

https://storage.googleapis.com/gctf-2020-attachments-project/ccef39c3c3d278908bbd0002788231c2cd5cd20a0e17f1654245dd9380c3b6cdfb760a40d60cbd0716a69182d95ac12466f44ff0309736fdbdbbbf5a7678f10f

oracle2.2020.ctfcompetition.com 1337