maybe i have to reconfigure interfaces enabled in octoprint server?
i mean I2C, SPI, serial, 1-wire, remote GPIO, VNC...
Referring to the sereial.log, the printer shuts down after receiving the initial command form OctoPrint to establish the connection:
Send: N0 M110 N0*125
A printer shot not react like that. My suggestion is: connect to a PC, start a program where you can send commands directly to the printer.
There you type in M110 N0 and see what happens
- when with pc i press on CONNECT i listen from PWC unit a "click" of switchoff (i think the relay) and again fast a "click" , is like a fast switch off-switch and stay ON:
- i sent the command you told me: M110 N0 , nothing happened
i have to chanke something on my marlin config.h? i had to reconfigure power supply to "2"...maybe is wrong?
i didn't change nothing else about power...uhm...
new log:
2020-04-18 23:33:41,531 - Connecting to: /dev/ttyS0
2020-04-18 23:33:41,539 - Changing monitoring state from "Offline" to "Opening serial port"
2020-04-18 23:33:41,546 - Connected to: Serial<id=0xb1a83dd0, open=True>(port='/dev/ttyS0', baudrate=250000, bytesize=8, parity='N', stopbits=1, timeout=10.0, xonxoff=False, rtscts=False, dsrdtr=False), starting monitor
2020-04-18 23:33:41,547 - Changing monitoring state from "Opening serial port" to "Connecting"
2020-04-18 23:33:41,556 - Send: N0 M110 N0*125
2020-04-18 23:33:47,498 - Unexpected error while reading serial port, please consult octoprint.log for details: SerialException: 'device reports readiness to read but returned no data (device disconnected or multiple access on port?)' @ comm.py:_readline:2823
2020-04-18 23:33:47,500 - Please see https://faq.octoprint.org/serialerror for possible reasons of this.
2020-04-18 23:33:47,502 - Changing monitoring state from "Connecting" to "Offline (Error: SerialException: 'device reports readiness to read but returned no data (device disconnected or multiple access on port?)' @ comm.py:_readline:2823)"
2020-04-18 23:33:47,505 - Connection closed, closing down monitor
2020-04-18 23:38:40,271 - Connecting to: /dev/ttyS0
2020-04-18 23:38:40,279 - Changing monitoring state from "Offline" to "Error: Connection error, see Terminal tab"
2020-04-18 23:38:40,285 - Unexpected error while connecting to serial port: /dev/ttyS0 SerialException: '[Errno 13] could not open port /dev/ttyS0: [Errno 13] Permission denied: '/dev/ttyS0'' @ comm.py:_openSerial:2691 (hook default)
Changing to #define POWER_SUPPLY 2 should not break something.
I assume that the USB connection reset causes the problem.
yes.. and maybe the problem is in marlin not octoprint....BUT when connected with usb to pc it have the energy to stay ON....
And that makes me curious
yes yes, when i press CONNECT the PWC switch off and than immediately switch on again ...i don't know why it switch off but the same i don't know why it switch on back one second after....
want see config.h?
I think, I found it.
One thing you may can try is this: Put tape on the 5V pin - Why and how
But I'm not quite sure it will help.
i go to read it....
i can do it but....i NO have wifi, i have a big switching power of 5volts for pi and camera is working, and it switch off evenif pi is disconnected (but it reconnect with the power of usb)
Referring to this https://github.com/makerbase-mks/MKS-TFT/issues/59, thy set #define POWER_SUPPLY to 2.
i know that post, i had follow it and thank it i solved same problem.
i had to reverse "+" and data cable on MKS GEN L V1.0 board, change pin and set "2" on power supply and another thing, because i have sensor BLTouch on pin "6" of servo1 i had to set the signal pin to 6 not 11... but this is not the problem....
now i tried this:
- i disconnect the cable from motherboard to PWC
- i connected from pc trought usb
i didn't had shut down
so the problem is: motherboard send a wrong signal to PWC and switch him off
One step forward, however.
Maybe you can figure out the issue in Marlin.
mks , tft and pwc are not news hardware...could i be the first unluky man with this issue? 
I'm sure you will handle this 
it seem like mks gen send M80 and m81 in wrong sequence......uhm....
i found this:
From Octoprint logo i read this quen i press CONNECT:
Connecting to: /dev/ttyUSB0
Changing monitoring state from "Offline" to "Opening serial port"
Connected to: Serial(port='/dev/ttyUSB0', baudrate=250000, bytesize=8, parity='N', stopbits=1, timeout=10.0, xonxoff=False, rtscts=False, dsrdtr=False), starting monitor
Changing monitoring state from "Opening serial port" to "Connecting"
Send: N0 M110 N0*125
and when there is "connecting to : /dev/ttyUSB0 the printer switch off!!!!
can someone help me? can i change this? Can i leave it ON while connecting?
I have to change something in Marlin?