This means your instance cannot access its own global IP address, which is a serious limitation of Oracle Cloud.
In the past I have used 2 other providers (DO and Hetzner) and I never came across such a problem.
For example I have just relaunched my node on DO as a genesis node and it worked fined. My command was: sn_node -m $(numfmt --from auto 40G) --first 104.248.129.139:5483 --skip-igd -vvvv --clear-data > v.log 2>&1 &
Running safe_network v0.7.18
============================
Jul 24 13:02:13.152 INFO safe_network::routing::routing_api: 7a4fb5.. Starting a new network as the genesis node (PID: 9217).
Jul 24 13:02:13.173 INFO safe_network::routing::routing_api: 2b2500.. Bootstrapped!
Node PID: 9217, prefix: Prefix(), name: 7a4fb5.., connection info:
"104.248.129.139:5483"
Jul 24 13:02:13.214 INFO safe_network::node::node_api: Node PID: 9217, prefix: Prefix(), name: 7a4fb5.., connection info: "104.248.129.139:5483"
Jul 24 13:02:13.257 INFO safe_network::node::event_mapping: Handling RoutingEvent: EldersChanged { elders: Elders { prefix: Prefix(), key: PublicKey(13eb..804c), remaining: {}, added: {7a4fb5(01111010)..}, removed: {} }, self_status_change: Promoted }
If anyone wants to connect to it, please go ahead. I will run it for 2 days.
Connection info is 104.248.129.139:5483 and node version is v0.7.18 (11 days old, but is the one specified by @stout77).