static css files not working in django 3 code example

Example 1: my django template doesnt want to load the static file

STATIC_URL = '/static/'
STATIC_ROOT = os.path.join(BASE_DIR, "/static/")

STATICFILES_DIRS = ( 
    STATIC_ROOT,        
)

Example 2: add static file in django

STATICFILES_DIRS = [
    BASE_DIR / "static",
    '/var/www/static/',
]