Hi cleggink,

I don't expect the library version to be a problem since 4.3.7 is also compatible with 7.0.x servers anyway.

But you could try to leverage the debug logging of the client library; please make sure that your project has also this dependency:

<dependency>
<groupId>com.lightstreamer</groupId>
<artifactId>java-system-out-log</artifactId>
<version>1.0.2</version>
</dependency>

and add this line of code just before the LightstreamerClient initialization:

LightstreamerClient.setLoggerProvider(new SystemOutLogProvider());

That will produce the log of the client library, maybe will help find some clues about the problem.

Regards,
Giuseppe