Error when trying to email customer an invoice

Shane is seeing the message "The parameters passed to the API were invalid. Check your inputs!"

Have you checked that your SMTP settings under Settings->Email are correct?

Wow, apparently we have been hacked. Mailgun shows 600,000 emails going out in the last 30 days, and our domain is now disabled

In the mailgun logs I am still seeing the "... Wants to Tell You About MILUS Snow Star" messages.

I have expired the old API key and our emails are going through. Not sure what else to do here. Is it possible these are just old messages that mailgun stored and is now allowing through?

Yes, that is entirely possible - let us know if it continues