Any errors produced while the daemon is starting are silenced

[warownia1]

Starting the daemon causes the parent process to exit immediately leaving the child process detached from the terminal with all file descriptors (including 0, 1 and 2) closed. It makes the daemon unable to display any uncaught errors.

Consider using python-daemon library which takes care of spawning daemons and pid files according to the PEP 3243.
Leave stderr open in debug mode.
Create a pipe to the parent process to send errors and notify of successful start or failure.