The connection to the gateway network fails

Dear all
I found and approved the following error on the main server after configuring Outgoing Connections. I have no clue why

Everything worked fine before

Can you give me some references? Thank you

Master server

sub server

Check in the target server's log for a more detailed message. If there isn't one, or it mentions a broken connection, then you are suffering from a firewall in your network path that doesn't support websockets.

Thank you. I'm verifying a network firewall issue. Does the screenshot below have an impact on gateway network

Can't tell. You've used a screen shot instead of posting the traceback as text/code. Please do so, so we can see the entire chain.