Hi Ike,

With the server log settings suggested in a previous post you should find these logs pertaining to a client session successfully bound to a websocket transport

26-Oct-23 09:32:33,112|INFO |L.connections |ACCEPT POOLED THREAD 8 |Accepted HTTP connection on "Lightstreamer HTTP Server" from 0:0:0:0:0:0:0:1:52916
26-Oct-23 09:32:33,800|INFO |L.requests |SERVER POOLED THREAD 10 |Serving request: /lightstreamer/create_session.txt?LS_protocol=TLCP-2.1.0 --> LS_polling=true&LS_cause=new.api&LS_polling_millis =0&LS_idle_millis=0&LS_cid=jqWtj1twChtfDxikwp1ltvc B4CJCJi kOj2CKDk&LS_adapter_set=WELCOME& on "Lightstreamer HTTP Server" from 0:0:0:0:0:0:0:1:52916
26-Oct-23 09:32:33,997|INFO |L.requests |SERVER POOLED THREAD 10 |Starting new session: S132b0001a335379aM2ccT3233994 (dotnet_standard_client 5.1.8 build 109) on "Lightstreamer HTTP Server" from 0:0:0:0:0:0:0:1:52916
26-Oct-23 09:32:34,046|INFO |L.pump |SERVER POOLED THREAD 10 |Session S132b0001a335379aM2ccT3233994 started.
26-Oct-23 09:32:34,077|INFO |L.connections |PUMP POOLED THREAD 8 |Reused HTTP connection on "Lightstreamer HTTP Server" from 0:0:0:0:0:0:0:1:52916
26-Oct-23 09:32:34,151|INFO |L.connections |SERVER POOLED THREAD 10 |Closed HTTP connection with internal cause code: 5 (Interrupted by client) on "Lightstreamer HTTP Server" from 0:0:0:0:0:0:0:1:52916
26-Oct-23 09:32:34,248|INFO |L.connections |ACCEPT POOLED THREAD 8 |Accepted HTTP connection on "Lightstreamer HTTP Server" from 0:0:0:0:0:0:0:1:52917
26-Oct-23 09:32:36,478|INFO |L.connections |ACCEPT POOLED THREAD 8 |Upgraded HTTP connection on subprotocol TLCP-2.1.0 on "Lightstreamer HTTP Server" from 0:0:0:0:0:0:0:1:52917
26-Oct-23 09:32:36,555|INFO |L.requests |SERVER POOLED THREAD 10 |Serving request: bind_session -> LS_cause=loop1&LS_session=S132b0001a335379aM2ccT32 33994& on "Lightstreamer HTTP Server" from 0:0:0:0:0:0:0:1:52917
26-Oct-23 09:32:36,559|INFO |L.requests |SERVER POOLED THREAD 10 |Attaching session: S132b0001a335379aM2ccT3233994 on "Lightstreamer HTTP Server" from 0:0:0:0:0:0:0:1:52917

In particular the two lines bolded are the upgrade to websocket of the http channel.
In case the Lightstreamer server responds with a 404 to the upgrade request, instead of the message 'Upgraded HTTP connection on subprotocol TLCP-2.1.0...,' a DEBUG-level message from the 'LightstreamerLogger.webServer' logger should appear with error details.