Server error

[01:43:47] [Server thread/INFO]: Starting minecraft server version 1.7.10
[01:44:41] [Server thread/INFO]: Loading properties
[01:44:41] [Server thread/INFO]: Default game type: SURVIVAL
[01:44:41] [Server thread/INFO]: Generating keypair
[01:44:42] [Server thread/INFO]: Starting Minecraft server on 25.117.50.245:25565
[01:45:08] [Server thread/INFO]: Preparing level "world"
[01:45:11] [Server thread/INFO]: Preparing start region for level 0
[01:45:12] [Server thread/INFO]: Preparing spawn area: 30%
[01:45:12] [Server thread/INFO]: Done (3.831s)! For help, type "help" or "?"
[01:53:10] [User Authenticator #1/INFO]: UUID of player xShamano is 64ea6a03-d186-47a0-b51f-eb58ebd8f62b
[01:53:11] [User Authenticator #2/INFO]: UUID of player Karakau190 is dcf0092a-e5e8-4354-9d4d-4a9d9b94dfbf
[01:53:13] [Server thread/INFO]: xShamano[/25.117.50.245:4553] logged in with entity id 81 at (-99.5, 64.0, 112.5)
[01:53:13] [Server thread/INFO]: xShamano joined the game
[01:53:16] [Server thread/WARN]: Can't keep up! Did the system time change, or is the server overloaded? Running 3413ms behind, skipping 68 tick(s)
[01:53:18] [Server thread/INFO]: Karakau190[/25.122.172.228:63298] logged in with entity id 82 at (-107.5, 60.0, 114.5)
[01:53:18] [Server thread/INFO]: Karakau190 joined the game
[01:53:25] [Server thread/INFO]: xShamano has just earned the achievement [Taking Inventory]
[01:54:08] [Server thread/INFO]: xShamano has just earned the achievement [Getting Wood]
[01:54:13] [Server thread/WARN]: Can't keep up! Did the system time change, or is the server overloaded? Running 2147ms behind, skipping 42 tick(s)
[01:54:20] [Server thread/INFO]: Karakau190 has just earned the achievement [Taking Inventory]
[01:54:29] [Server thread/INFO]: Stopping server