Error from 1 client

I get this error from one client, repeats every minute

1824 2015-11-30 16:33:27 Client [ScheduleAgentThread] ScheduleAgent - Run Exception in Run: Client found response content type of ‘text/html; charset=UTF-8’, but expected ‘text/xml’.The request failed with an empty response.

What is this?


Could you please tell me, what CMS and player version do you use?
Is your device properly connected to the internet and CMS(address/key)?
In CMS do you see this device as ‘logged in’? What’s in the status column?