can't connect to HBase any more

[ma qiang]

I connect to HBase using HBaseAdmin and HTable class succefully,
suddenly  can't manipulate HBase and the error print as belows:

java.net.SocketTimeoutException: timed out waiting for rpc response
        at org.apache.hadoop.ipc.Client.call(Client.java:484)
        at org.apache.hadoop.ipc.RPC$Invoker.invoke(RPC.java:184)
        at $Proxy0.deleteTable(Unknown Source)
        at org.apache.hadoop.hbase.HBaseAdmin.deleteTable(HBaseAdmin.java:169)
        at hbasetest.DeleteTable.main(DeleteTable.java:29)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at 
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at 
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.apache.hadoop.util.RunJar.main(RunJar.java:155)

Can you tell me why and how to solve this problem. Thank you very much.

Best wishes;