Internal server error when qbo api call response not ok #6

Internal Server Error: /quickbooks/qbo_request
Traceback (most recent call last):
  File "/usr/local/lib/python3.9/site-packages/django/core/handlers/exception.py", line 47, in inner
    response = get_response(request)
  File "/usr/local/lib/python3.9/site-packages/django/core/handlers/base.py", line 181, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/Users/michiel/gh/pondersource/peppol-python-demo/quickbooks/views.py", line 122, in qbo_request
    return HttpResponse(' '.join([response.content, str(response.status_code)]))
TypeError: sequence item 0: expected str instance, bytes found