could not get list of sessions from appium server

I, and others, have run into many cases where we want to control an automation session which is already in progress, but cannot share the client object itself. This is the only state a client object needs to keep, and we can take advantage of this to unlock some useful flexibility. All the client libraries automatically save the session ID when a sessions is started and include in in the path for all further commands. When it comes to your test script, the only thing which differentiates the client (sometimes called driver) object from the client for a different test, is the session ID. A device will not be reused for a session until the session is ended via an HTTP DELETE request sent to /session/:sessionId. Since Appium has a one-to-one relationship between sessions and devices, if a session is already running, any new sessions will automate other devices available to the Appium server.

Webdriver HTTP commands after the initial POST to the /session endpoint all have paths which start with /session/:sessionId, where :sessionId is the unique identifier for this session, returned in the initial /session response. Every Appium automation session is given a unique ID when the session is first created.

Could not get list of sessions from appium server