Mailgun 404 error with Pythonanywhere - django

Question

I'm trying to use mailgun in my Django project hosted on Pythonanywhere.
In my WSGI file, I have:
os.environ['DJANGO_MAILGUN_SERVER_NAME'] = 'https://api.mailgun.net/v3/sandboxnumbersomething.mailgun.org/messages'
os.environ['DJANGO_MAILGUN_API_KEY'] ='mykey'
and my settings are:
# EMAIL
# ------------------------------------------------------------------------------
DEFAULT_FROM_EMAIL = env('DJANGO_DEFAULT_FROM_EMAIL',
default='Apitrak <noreply#apitrak.com>')
EMAIL_BACKEND = 'django_mailgun.MailgunBackend'
MAILGUN_ACCESS_KEY = env('DJANGO_MAILGUN_API_KEY')
MAILGUN_SERVER_NAME = env('DJANGO_MAILGUN_SERVER_NAME')
When my app fire an email (for example at signup), I have a 404 error:
MailgunAPIError at /accounts/email/
<Response [404]>
Request Method: POST
Request URL: https://vincentle.pythonanywhere.com/accounts/email/
Django Version: 1.8.6
Exception Type: MailgunAPIError
Exception Value:
<Response [404]>
Exception Location: /home/vincentle/.virtualenvs/apitrak/lib/python3.4/site-packages/django_mailgun.py in _send, line 154
Python Executable: /usr/local/bin/uwsgi
Python Version: 3.4.0
Python Path:
['/var/www',
'.',
'',
'/var/www',
'/home/vincentle/.virtualenvs/apitrak/lib/python3.4',
'/home/vincentle/.virtualenvs/apitrak/lib/python3.4/plat-x86_64-linux-gnu',
'/home/vincentle/.virtualenvs/apitrak/lib/python3.4/lib-dynload',
'/usr/lib/python3.4',
'/usr/lib/python3.4/plat-x86_64-linux-gnu',
'/home/vincentle/.virtualenvs/apitrak/lib/python3.4/site-packages',
'/home/vincentle/apitrak']
Server time: Tue, 17 Nov 2015 16:02:28 +0100
I've tried a curl in the virtualenv of my WebApp:
curl -s --user 'api:key-NUMBERS' https://api.mailgun.net/v3/NUMBERS.mailgun.org/messages -F from='Excited User <excited#samples.mailgun.org>' -F to='vincent#vincentle.fr' -F subject='Hello' -F text='Testing some Mailgun awesomeness!'
And this works OK.

Answer 1

The setting DJANGO_MAILGUN_SERVER_NAME should be a domain name, not a url.
Try the following:
os.environ['DJANGO_MAILGUN_SERVER_NAME'] = '<sandboxnumbersomething>.mailgun.org'
From the readme:
Replace SERVER-NAME with the last part of your "API Base URL" (e.g. https://api.mailgun.net/v3/<your_server_name>), also found in your Mailgun account details.