OpenLiteSpeed Django app give errors when save very simple model in admin view

I have an OpenLiteSpeed Django app in Google Cloud Compute Engine which connects a SQLite DB. I’ve created some models and views, in these views I can show lists from SQLite data. I am also able to list and search the data in admin views. However in admin view when I try to make some changes and save or delete mostly get 500 Internal Error, it works rarely.
Model that I try to make changes or add new item:


from django.db import models

class Test(models.Model):
    num = models.DecimalField(default=0.00, max_digits=10, decimal_places=2)

I cannot debug on server, to see errors I check stderr.log file in project directory. Following errors occur when I get 500 Internal Error on admin view page:

UnicodeDecodeError: ‘utf-8’ codec can’t decode byte 0xdd in position 7: invalid continuation byte

The above exception was the direct cause of the following exception:

SystemError: <class ‘lsapi_wsgi.Request’> returned a result with an error set
Not Found: /favicon.ico
2020-05-16 06:31:45.902022 [ERROR] [1643] wsgiAppHandler failed to create req_obj.

If there is a way to debug on compute engine please share.
Btw on my local environment it works perfectly.