Octoprint loses connection to printer on laptop as server

Would be very nice if someone could help me with this problem :grinning:

What is the problem?
Octoprint loses the connection after a while (nearly an hour) of printing when I am entering the room with the printer in it. I didn't even touched the cable or anything else.

What did you already try to solve it?
Restart printer and octoprint
changing the usb cable

Logs (octoprint.log, serial.log or output on terminal tab, browser error console ...)

2019-08-29 20:52:34,466 - octoprint.util.comm - ERROR - Unexpected error while reading from serial port
Traceback (most recent call last):
  File "/home/herbert/OctoPrint/venv/local/lib/python2.7/site-packages/octoprint/util/comm.py", line 2739, in _readline
    ret = self._serial.readline()
  File "/home/herbert/OctoPrint/venv/local/lib/python2.7/site-packages/octoprint/util/comm.py", line 4844, in readline
    c = self.read(1)
  File "/home/herbert/OctoPrint/venv/local/lib/python2.7/site-packages/serial/serialposix.py", line 501, in read
    'device reports readiness to read but returned no data '
SerialException: device reports readiness to read but returned no data (device disconnected or multiple access on port?)
2019-08-29 20:52:34,468 - octoprint.util.comm - ERROR - Please see https://faq.octoprint.org/serialerror for possible reasons of this.
2019-08-29 20:52:34,498 - octoprint.util.comm - INFO - Changing monitoring state from "Printing" to "Offline (Error: SerialException: 'device reports readiness to read but returned no data (device disconnected or multiple access on port?)' @ comm.py:_readline:2739)"

Additional information about your setup (OctoPrint version, OctoPi version, printer, firmware, browser, operating system, ...)
Octoprint is running on an laptop with linux installed on it.
There usb camera on it. Instead I am using an old phone with IP webcam on it.
OctoPrint : 1.3.11
Printer : Ender 3

This might be the Ender 3, your firmware, power on the Ender 3. You might search the Ender 3 forum space to see if others have experienced this, too.

Hey I had the same issue but I didn't just enter the room, I also turned on the light. Turned out it was enough to interrupt the connection (to be specific turning off the light interrupted it).
I switched to my own configured marlin (nothing special just ender 3 config with bltouch) and the problem disappeared.

Thany your for your answers.
I changed the firmware to plain marlin and hope that this solved the problem.