500 error when sending a form to mailgun

[bradrice]

I'm trying to use a coderedcms form page to create a contact form. It works fine, echoing to the command line locally, but when I use it on my server I get a 500 error when I submit. I don't get anything very useful in the logs to figure out what is going on. This is my prod setup for the anymail setup to send email to the Mailgun api. I can send using the command line with curl from the server.

EMAIL_BACKEND = "anymail.backends.mailgun.EmailBackend"
DEFAULT_FROM_EMAIL = "admin@mail.oh-joy.org"
SERVER_EMAIL = "admin@mail.oh-joy.org"
MANAGERS = ADMINS
ANYMAIL = {
    "MAILGUN_API_KEY": os.environ.get("MAILGUN_API_KEY"),
    "MAILGUN_SENDER_DOMAIN": "mail.oh-joy.org",
}

I don't see anything in the docs to help me. I do find the submission is putting the form into the sqllite3 db fine, but when it submits I get

Internal server error
Sorry, there seems to be an error. Please try again soon.
Any help would be appreciated.

[medmunds]

@bradrice You'd expect a 500 "Internal server error" means some sort of temporary outage at Mailgun, and "please try again soon" would seem to fit with that. You might check https://status.mailgun.com/.

But you said sending worked with curl. And Mailgun has a history of using incorrect http status codes and cryptic error messages to indicate actual problems with the request.

I'm not familiar with coderedcms, so I don't know what its contact form might be doing. Does this happen every time you submit the form, or does it sometimes work?

Here are some common problems you might check:

• It looks like you might be using an env file. Does it have a # comment on the MAILGUN_API_KEY line? (Line end comments aren't supported in env files, so that would cause the API key to be loaded incorrectly.)
• If your account is provisioned for Mailgun's European servers, be sure to set Anymail's MAILGUN_API_URL to their EU endpoint. (Anymail defaults to Mailgun's original US servers.)
• In your contact form's code, are you specifying a from_email? If so, is it an address in your @mail.oh-joy.org domain? (If you're trying to send from the user who filled out the form, that won't work—use reply_to instead. And if you're trying to send from an address @oh-joy.org without the mail subdomain, you may need to separately verify your top-level domain at Mailgun.)

If none of that helps, there are two other troubleshooting steps that might be useful:

1. Use Django's command-line sendtestemail to send a message to yourself. If that works, the problem is in your contact form or the way it sends a message. If that fails, the problem is with your Anymail Mailgun configuration.
2. Enable Anymail's DEBUG_API_REQUESTS to capture the raw Mailgun API request. You might spot an obvious problem in that, or you can compare it to the curl API request that worked and try to narrow down the difference.