PHPMailer MIME email sent via Mailgun API with curl gives error. Test code:
<?php
$ch = curl_init();
$data = ['msg' => $mimeContent];
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);
?>
Based on my own experience working with Mailgun API, I found that creating MIME emails without the official library often leads to issues related to how the data is passed. I overcame similar problems by ensuring that the headers and the payload were correctly formatted so Mailgun could parse the MIME content. I remember spending a few days adjusting curl options, particularly setting the correct content type for the multipart form data and verifying the parameter names matched the documentation exactly. This careful tuning helped eliminate the errors I was initially encountering.
In my experiments I discovered that a common mistake is not aligning the key names with what Mailgun expects. I solved my own issue by changing the parameter from ‘msg’ to ‘message’ and explicitly setting the content type for MIME data. It also helped to verify that the MIME encoding was in the correct format since even slight deviations could trigger rejection by Mailgun’s API. Double-checking small configurations like these saved a lot of debugging time and ensured reliable email transmissions.