Your API is open to the world… This is generally not a good thing in most setups.
You should definitely change that from 0.0.0.0 to 127.0.0.1 unless you’ve got iptables setup to route port 5001 to some secured program/proxy/something.
Your config has an IPv4 address in an ip6 field. You should be able to obtain your Linode’s ip6 address by looking at the output of:
ip a
while logged into your Linode.
Here’s Linode’s IPv6 FAQ if you’re not sure about their IPv6 support or would like to find your IPv6 address via their web interface.
According to your netstat output, port 8080 is only accessible from localhost. Perhaps you have another service running on port 8080 ?
What is the output of:
sudo lsof -ni4 |grep 8080