Ok, I've seen people complain about not being able join the server during the time 11:00AM to 4:00PM (GMT+5.5). It also happend that one day my brother told me that he couldnt log in the whole day. It is not that the server is offline, i tried manually pinging the server with CMD and it got a response; that means the server is online, but due to some bug we aren't able to log in. Here is the Log from my client, it show that
[14:10:45] [Client thread/INFO]: Connecting to play.sentinelcraft.net, 25565
[14:11:06] [Server Connector #1/ERROR]: Couldn't connect to server
java.net.ConnectException: Connection timed out: no further information: play.sentinelcraft.net/108.174.60.54:25565
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method) ~[?:1.7.0_45]
at sun.nio.ch.SocketChannelImpl.finishConnect(Unknown Source) ~[?:1.7.0_45]
at io.netty.channel.socket.nio.NioSocketChannel.doFinishConnect(NioSocketChannel.java:191) ~[NioSocketChannel.class:?]
at io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe.finishConnect(AbstractNioChannel.java:228) ~[AbstractNioChannel$AbstractNioUnsafe.class:?]
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:497) ~[NioEventLoop.class:?]
at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:447) ~[NioEventLoop.class:?]
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:341) ~[NioEventLoop.class:?]
at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:101) ~[SingleThreadEventExecutor$2.class:?]
at java.lang.Thread.run(Unknown Source) ~[?:1.7.0_45]
[14:13:17] [Client thread/INFO]: Connecting to play.sentinelcraft.net, 25565
[14:13:38] [Server Connector #2/ERROR]: Couldn't connect to server
java.net.ConnectException: Connection timed out: no further information: play.sentinelcraft.net/108.174.60.54:25565
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method) ~[?:1.7.0_45]
at sun.nio.ch.SocketChannelImpl.finishConnect(Unknown Source) ~[?:1.7.0_45]
at io.netty.channel.socket.nio.NioSocketChannel.doFinishConnect(NioSocketChannel.java:191) ~[NioSocketChannel.class:?]
at io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe.finishConnect(AbstractNioChannel.java:228) ~[AbstractNioChannel$AbstractNioUnsafe.class:?]
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:497) ~[NioEventLoop.class:?]
at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:447) ~[NioEventLoop.class:?]
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:341) ~[NioEventLoop.class:?]
at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:101) ~[SingleThreadEventExecutor$2.class:?]
at java.lang.Thread.run(Unknown Source) ~[?:1.7.0_45]
[14:13:52] [Client thread/INFO]: Stopping!
Please look into this issue, its now becoming common.