Resolved Client-server connection no longer valid - SOLVED

Hello there, i installed SB on my Ubuntu 20.04 server (without DE) in (OVH)cloud trough steamCMD; i don't use "screen" command because Starbound server run as a service; ufw and iptables are inactive, just serverfarm hardware firewall is active and these are the rules:

Server and client are same version 1.4.4 (64bit) and both don't have mods installed, as you can see on logs below.
I connect it from my home pc and when i check "skip tutorial" all work fine but if i want to run the tutorial so i uncheck "skip tutorial" i receive "Client-server connection no longer valid".
Appear random, sometime simply i can't connect, other time i connect but i lost connection in 10 seconds or in 1 minute.... the errore is the same: "Client-server connection no longer valid".
The problem is 100% network related i think, because, as you can see on logs, there aren't errors before disconnection.
Maybe tutorial use different port so i must open ports on client router also? (i already open 21025 tcp & UDP, 21026 tcp and 21027 tcp)
Or maybe there is some port to control connection so server try to connect to client?
Please help me to understand the problem, i'm going crazy.

To extract logs below i have before deleted universe on server and all file in storage folder on client so like fresh install; after i start server as a service and i created new character with "skip tutorial" unchecked on client

This my server config:
https://pastebin.com/NpvCbska

This my server log from start to quiet after disconnection error:
https://pastebin.com/WQzNg1n2

This is my client log from start to quit:
https://pastebin.com/0wF6Lnaj

Many thanks for your time ;-)

 

Hi to all, i am I'm here again.
Specially a big thanks to Chucklefish staff/devs for their help... ..........
Finally after investigating dozens of hours I found and solved the problem and i hope this can help someone who was going crazy like me for this random error "Client-server connection no longer valid".
Reasons can be many but in my case starbound_server service was killed by the os because out of memory; it was very difficult to understod because it only happen with tutorial.
I understod that by running the server manually without service; on shell window appeared "Killed".
Anyway, to solve you can stop other services/app, making a swap file or upgrading ram.
while you connect from the client, check the ram usage on the server, if it reaches 100 you are over... ;-)