AnymailRequestsAPIError: Sending a message to gmail.comj from MIT Bootcamps <[email protected]

[sentry-io]

Sentry Issue: BOOTCAMPS-9X

AnymailRequestsAPIError: Sending a message to [REDACTED]@gmail.comj from MIT Bootcamps <[email protected]
Mailgun API response 400 (BAD REQUEST):
{
  "message": "'to' parameter is not a valid address. please check documentation"
}
(3 additional frame(s) were not displayed)
...
  File "anymail/backends/base.py", line 95, in send_messages
    sent = self._send(message)
  File "anymail/backends/base_requests.py", line 60, in _send
    return super(AnymailRequestsBackend, self)._send(message)
  File "anymail/backends/base.py", line 125, in _send
    response = self.post_to_esp(payload, message)
  File "anymail/backends/base_requests.py", line 82, in post_to_esp
    self.raise_for_status(response, payload, message)
  File "anymail/backends/base_requests.py", line 94, in raise_for_status
    backend=self)

Error sending email 'Verify your email' to ["[REDACTED]@gmail.comj"]