Once cannot start the system/session but twice

Hi,
The main problem is actually not same as the title.
My project is a EEG board based on ESP32 with ADS1299. I'm testing the Cyton Wifi module, now the code is basically done and it can implement normal data interaction with OpenBCI GUI version 4.1.2.

The first problem is, although the board can start session with GUI, it can't start streaming with version 5.0.4 and further version, I'm guessing if there is any change in the protocol that I don't know. It can open an access point with WiFi.softAP(ssid, password) this sentence, and my PC can connect this AP, but the streaming can't start. The log shows that Exception when starting stream, Errror in start_stream:BOARD_WRITE_ERROR. I have looked the source code of the GUI, but the code is way too complex, I can't locate what cause this problem.

The second problem is, I have set the default state of the ADS1299, my tutor's document said it should be BIAS DON'T INCLUDE & SRB1 OFF & SRB2 OFF, and that's what I write into the register CHnSET, I found that every channel is actually in the state I had set. But the GUI can't read my settings for every channel, it shows BIAS INCLUDE & SRB2 ON & SRB1 OFF in the Hardware Settings. But the other code project of my board, which is based on serial transfer, the hardware settings will be read actually by the GUI. Why the GUI can't read my settings for ADS1299 in CHnSET register?

And the third problem is the new one, when my PC get connect to my board's AP , what I supposed to do is start up the GUI right? But when I finished the Cyton settings and clicked the start system button, the GUI did not change into the analysis window that contains FFT diagram and wave and etc but showed what it was before I clicked the button which was empty. And I clicked the button again, the GUI finally showed the full diagram and can start the data stream.