Daemon. AttributeError: 'NoneType' object has no attribute 'fileno'

Question

Please help me with the error. I have a simple code that I run on Linux.

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import daemon
import sys
from traceback import format_exc


def run_main_function():
    print("Hello")

try:
    with daemon.DaemonContext():
        run_main_function()
except:
    print(sys.stdin)
    print(format_exc())

The script is unstable. The script sometimes fails and sometimes executes successfully. I ask for help in solving the problem.

None
Traceback (most recent call last):
  File "/usr/lib/zabbix/externalscripts/logstash_stats.py", line 18, in <module>
    with daemon.DaemonContext():
  File "/usr/local/lib/python3.9/site-packages/daemon/daemon.py", line 249, in __init__
    detach_process = is_detach_process_context_required()
  File "/usr/local/lib/python3.9/site-packages/daemon/daemon.py", line 817, in is_detach_process_context_required
    if is_process_started_by_init() or is_process_started_by_superserver():
  File "/usr/local/lib/python3.9/site-packages/daemon/daemon.py", line 795, in is_process_started_by_superserver
    if is_socket_file(sys.__stdin__):
  File "/usr/local/lib/python3.9/site-packages/daemon/daemon.py", line 759, in is_socket_file
    file_fd = file.fileno()
AttributeError: 'NoneType' object has no attribute 'fileno'

I tried to set stdin manually, but it didn't work.
Google search didn't help me.

New details: The problem is not related to the daemon library. My script periodically returns NoneType when I execute simple code.

import sys

print(sys.stdin) 

return:

None

My script calls zabbix. The rights to the script were issued correctly. I do not know what the problem is.

chown zabbix:zabbix /path/script
chmod 0777 /path/scrypt

Tell me what can be done?