Sorry but we couldn't find any hint.
I see that other clients were working at the same time.
Can you replicate the issue with your own client in a test environment
or have you just noticed the issue by analyzing your logs?
In the first case, what do you see on the client?

Also, in the first case, please add the configuration of the "LightstreamerLogger.connections" logger at DEBUG level and collect a new log.
You can send us the log through a private message, if you wish.

By the way, the DEBUG messages about the "Inbound closed" are normal and notify of clients which close the connection without performing the closure handshake.