ValueError: Incorrect timezone setting while migrating manage.py file in Django

According to the documentation:

TIME_ZONE

Default: 'America/Chicago'

A string representing the time zone for this installation, or None.

Instead of utc+6.00, set the TIME_ZONE to Asia/Dhaka:

TIME_ZONE = 'Asia/Dhaka'

In simple words you need to choose your timezone from this list