Hi,
I have moved this post back to the relevant thread.

It is no surprise that, by limiting the connection to http polling nothing has changed.
In fact, in your case, there is no answer from the Server since the initial connection, before the client ever tries websocket or http streaming.
I see that the client receives a "Socket error" message from the low-level "DotNetty" library.

Unfortunately, no further indication is logged.
For this reason, if you can manage to get a packet capture, this may provide some clue.
Otherwise, can you try a simple manual request from the same context of your application, to see what happens?
For instance, you can just issue https://push.cityindex.com/