Download a generated CSV file with Django Rest Framework and ReactJS

I'm trying to download a a simple CSV file to get the email addresses of my users based on when they signed up. I can't seem to get the frontend ReactJS and backend Django to play nice with one another:

urls.py

...
url(r'^api/email-export/$', app.api_views.EmailExportView.as_view()),
...

api_views.py:

from rest_framework.views import APIView

class EmailExportView(APIView):
    authentication_classes = [TokenAuthentication]
    permission_classes = [IsAdminUser]
    def get(self, request, format=None):
        user_emails = User.objects.filter(...)
        response = HttpResponse(content_type="text/csv")
        response["Content-Disposition"] = "attachment; filename='user_emails.csv'"
        writer = csv.DictWriter(response, fieldnames=["email"])
        writer.writeheader()
        for email in user_emails:
            writer.writerow({"email": email})
        return response

and in my react file

import { AdminApiClient } from "./apiClient";

type Props = {
  apiClient: AdminApiClient;
};

export function EmailExportPage({ apiClient }: Props) {

  const [startDate, setStartDate] = useState(new Date());
  const downloadCsv = () => {
    apiClient.emailExport(startDate)
  }

  return (
    ...
    <Form onSubmit={downloadCsv}>
      <Button type="submit">Download</Button>
    </Form>
  )

apiClient.ts is a file with a helper class that performs api calls

import axios, { AxiosInstance } from "axios";

export class AdminApiClient {
  apiToken: string;
  client: AxiosInstance;

  async emailExport(query: Date): Promise<any> {
    const resp = await this.client.get("/api/email-export/", {
      params: { query },
    });
    return resp;
  }
}

When I hit the download button now, I get a weird error in the terminal:

[15/Jul/2020 17:35:16] "GET /api/email-export/?query=2020-07-15T07:34:45.691Z HTTP/1.1" 200 7
Traceback (most recent call last):
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/logging/__init__.py", line 868, in emit
    msg = self.format(record)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/logging/__init__.py", line 741, in format
    return fmt.format(record)
  File "/Users/me/.local/share/virtualenvs/my-project/lib/python2.7/site-packages/django/utils/log.py", line 173, in format
    if args[1][0] == '2':
IndexError: tuple index out of range
Logged from file basehttp.py, line 85