Prompt not detected - upload failed. Trying to recover...

I run a example in STM32F4DISCOVERY board.
I copied the example code like this:

let WIZnet = require("WIZnet");


E.on('init', function () {
  SPI2.setup({ mosi:B15, miso:B14, sck:B13 });
  let eth = WIZnet.connect(SPI2, B10);
  eth.setIP();
});
save();

But is's not okay.

Prompt not detected - upload failed. Trying to recover...Execution Interrupted during event processing.

I do have the library WIZnet in board.
I want to konw how connect to Internet stably by Ethernet cable?

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Then I changed the code like this:

let WIZnet = require("WIZnet");

setTimeout(()=>{
  SPI2.setup({ mosi:B15, miso:B14, sck:B13 });
  let eth = WIZnet.connect(SPI2, B10);
  eth.setIP();
},2000)

E.on('init', function () {

});
save();

that's okay. But the new question is, If i closed the power of the board and then reopened it, It couldn't access to network, I couldn't ping the static ip of the board.

It seems that I have to run code after I access the board by IDE!

I wonder when and where I access to network is better.