Connection to server java.net.SocketException: Socket closed - sockets

Question

I'm trying to connect to my google vps server, but constantly getting error :
java.net.SocketTimeoutException: timeout
java.net.SocketException: Socket closed
I've created system service on my server, which listens on the port 8080. I've forwarded the default http traffic to port 8080 and made sure ports 80 & 8080 are open:
iptables -t nat -I PREROUTING -p tcp --dport 80 -j REDIRECT --to-ports 8080
sudo iptables -A INPUT -p tcp --dport 80 -j ACCEPT
sudo iptables -A INPUT -p tcp --dport 8080 -j ACCEPT
I've also saved the iptable rules :
sudo apt-get install iptables-persistent
I've checked if the service actually listens on the port by sudo netstat -tunlp:
tcp6 0 0 :::8080 :::* LISTEN 5789/java -> it does
This is my retrofitBuilder in app, which is trying to connect to server with standard http port :
return Retrofit.Builder()
.baseUrl("http://34.118.22.134/")
.addConverterFactory(MoshiConverterFactory.create())
.build()
.create()
}
When testing the service locally, it works as expected,also the service on the servers works fine.
When I do sudo ss -ltnp, I see that port 80 is not in "listening state", only port 8080 and several others are. I dont want to use uwf to enable it because that will disrupt the SSH connection.
The postman can't reach server as well and it's throwing 500-internal server error.
I do not manipulate sockets in code in any way.