My main.py code keeps crashing randomly. Getting the following error in core py files

[Akshul-pirhoalpha]

Getting error in backend.py file. What does handler method does? And why this error is persistent across multiple boards. It can occur randomly in a few hours, to a day or two or more.

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/thonny/plugins/micropython/backend.py", line 340, in handle_command
    response = handler(cmd)
  File "/usr/lib/python3/dist-packages/thonny/plugins/micropython/backend.py", line 689, in _cmd_Run
    self._execute(cmd["source"])
  File "/usr/lib/python3/dist-packages/thonny/plugins/micropython/backend.py", line 441, in _execute
    return self._process_until_raw_prompt(capture_output)
  File "/usr/lib/python3/dist-packages/thonny/plugins/micropython/backend.py", line 538, in _process_until_raw_prompt
    ddd = self._connection.soft_read_until(BLOCK_CLOSERS, timeout=0.05)
  File "/usr/lib/python3/dist-packages/thonny/plugins/micropython/connection.py", line 46, in soft_read_until
    return self.read_until(terminator, timeout, timeout_is_soft=True)
  File "/usr/lib/python3/dist-packages/thonny/plugins/micropython/connection.py", line 56, in read_until
    self._check_for_error()
  File "/usr/lib/python3/dist-packages/thonny/plugins/micropython/connection.py", line 106, in _check_for_error
    raise ConnectionClosedException(self._error)
thonny.plugins.micropython.connection.ConnectionClosedException: device reports readiness to read but returned no data (device disconnected or multiple access on port?)
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/thonny/plugins/micropython/backend.py", line 340, in handle_command
    response = handler(cmd)
  File "/usr/lib/python3/dist-packages/thonny/plugins/micropython/backend.py", line 689, in _cmd_Run
    self._execute(cmd["source"])
  File "/usr/lib/python3/dist-packages/thonny/plugins/micropython/backend.py", line 441, in _execute
    return self._process_until_raw_prompt(capture_output)
  File "/usr/lib/python3/dist-packages/thonny/plugins/micropython/backend.py", line 538, in _process_until_raw_prompt
    ddd = self._connection.soft_read_until(BLOCK_CLOSERS, timeout=0.05)
  File "/usr/lib/python3/dist-packages/thonny/plugins/micropython/connection.py", line 46, in soft_read_until
    return self.read_until(terminator, timeout, timeout_is_soft=True)
  File "/usr/lib/python3/dist-packages/thonny/plugins/micropython/connection.py", line 56, in read_until
    self._check_for_error()
  File "/usr/lib/python3/dist-packages/thonny/plugins/micropython/connection.py", line 106, in _check_for_error
    raise ConnectionClosedException(self._error)
thonny.plugins.micropython.connection.ConnectionClosedException: device reports readiness to read but returned no data (device disconnected or multiple access on port?)

>>> 
Connection lost (device reports readiness to read but returned no data (device disconnected or multiple access on port?))

Use Stop/Restart to reconnect.

[robert-hh]

The error message just says that Thonny lost the connection. Nothing about the code on the board. If there is no code running at the board which could be the reason, check the cables, wiring, breadboard, etc...

[Akshul-pirhoalpha]

Even when my borad is not connected to thonny, if I have it connected directly to mains supply and it has main.py file that runs automatically, then also the code is freezing up. Or I have it connected to PC via minicom. So what can be the reason in that case?

[robert-hh]

Hard to say unless you have error messages from the board. Try connecting it with a simple tool like Putty, etc. They do not show that series of internal error messages.

[Akshul-pirhoalpha]

I have connected it with minicom and it never gave the internal error. But the statement that got printed before the above error was same as when connected to minicom. So mostly it freezes up when it is posting using the LTE module interfaced with rp2040. So I am now thinking that same issue might be possible even when the mcu is directly powered. Some issue with internal micropython core files.

[robert-hh]

Did you update the rp2 firmware to the most recent nightly build? Just to be sure not to search for an error that has already been solved.

[Akshul-pirhoalpha]

I have downloaded and programmed again with the latest nightly build. Have put on debugging.