Error when uploading profile picture

Hello @karinthygesen and @yuriinalivaiko

We are having the exact same problem with our site, also with simply.com as the provider.
Seems to have started a few days ago. It’s also an error 455 from admin-ajax.php, when trying to upload anything.
I’ve been in touch with simply.com over the past few days and they replied with “Malformed multipart body” and that it seems to be an issue with the plugin Ultimate Member.
Sadly I have nothing further to add, but really hoping for a solution, as this hinders our work significantly.

Good day to the both of you! 🙂

@karinthygesen

Yes that’s right, there is an empty field undefined by the end of the upload.

You can try this code snippet, which will remove the undefined with empty name.
I have tested this code snippet at my site even if the bad undefined is ignored by my hosting server and with the code snippet active the upload looks clean.

add_action('wp_footer', function() { ?>
    <script type="text/javascript">
    (function() {
        var originalAppend = FormData.prototype.append;
        FormData.prototype.append = function(name, value, filename) {
            if (!name || name === 'undefined' || value === 'undefined') {
                return;
            }
            if (arguments.length === 3) {
                originalAppend.call(this, name, value, filename);
            } else {
                originalAppend.call(this, name, value);
            }
        };
    })();
    </script>
    <?php
});

You install the code snippet by adding it to your active theme’s functions.php file or use the “Code Snippets” Plugin

https://wordpress.org/plugins/code-snippets/