What is the network on the failed system ? cellular ?
From what ? the other node ?
I was able to connect to 65930 this morning
553181 did not allow a connect, so the issue seems to be with that node.
Being NNX, you should probably review that part of your setup, especially if that was a recent change to NNX.
reg data = 553181=radio@202.90.241.21:4570/553181,202.90.241.21
I could connect both ways from either node yesterday for a short time
553181 has been up for quite some time now and working, I did try and setup another NNX note but that did the same, so I requested another plan node to see if that would work
I could alway change the NNX node back to a normal node and see if that works any different
Perhaps a look at the extensions.conf for the inbound route for connection.
Or even possibly a firewall issue.
ufw status
But you really should test this node for inbound and outbound with each config change. It probably helps to have a friend test with that is outside your network.
Verifying that it does have a nodelist file in /var/lib/asterisk and that it is up-to-date may go a long way.
systemctl restart asl3-update-nodelist
Just watching the asterisk in the foreground @ CLI> may reveal the error during connection attempt.
If you see it, post it here.
edit:
I would concentrate on the outbound connection. For it is not effected by any port routing issues.