Hi Alfredo,

Indeed, the "501, Not Implemented" reject should be issued by the Lightstreamer server without involving the Adapters.
There are a few cases that can result in that error and all involve a syntax error or a badly-formatted value in the HTTP protocol. For example, the use of an unexpected method, or if you specify a "Transfer-Encoding" when using 1.0 version.

Please verify that your control request, from the point of view of HTTP protocol, contains no errors or differences compared with the create and bind requests.

Furthermore, if you could have the server log, setting the INFO level to "LightstreamerLogger.connections" logger, you should find a more precise indication about the type of the error.

Hope that helps.