Connection to server up to 3000-4000ms! - The problem is in internet route. Responses must not exceed 600ms. Check the route to the server you are using. Somewhere on the route, there are package losses. For this, use MTR software for Windows and find out, where losses occur on the route.
If you are using WiFi, this is also can be a reason. For SkyDe, it is not recommended. Only stable internet connection.