I've correctly added my server: http://www.gametracker.com/server_info/185.2.136.156:2552/

I'm using DayZ Chernarus as current map.

The map is showed correctly in the "favorite maps" field, but in the banner is displayed as " current map: unknown "

Thanks for help in advance ^_^

Your server is not reporting a map name. You may want to review changes you have recently made to the server to determine what exactly caused it.

I'm assuming the reason it shows a map name in the graph was because your server WAS reporting the map name sometime in the past week, but something was changed to cause your server not to report it.