Error during upload, but its not an error

Question

Im trying to do a simple upload file to a server, ok, he does that correctly. But, when I send a document with size 1MB or more it returns an error but the file appears on the server anyway. It succeed. But he says "Error during upload" (on red) on the screen How I fix that? (sorry for the bad english)

I've tried to put "onload: (response) => response.key" But not happen.

This is my upload.js It works, but if the file has 1MB or more will show an error and its bad because the doc was send correctly on the server.

FilePond.setOptions({
    server: {
      url: 'https://server.example.com',
        process: {
            url: '/upload-file',
            method: 'POST',
            withCredentials: false,
            headers: {},
            timeout: 7000,
            onload: null,
            onerror: null,
            ondata: fd => {
              fd.append('first_id', '08711913000128');
              fd.append('second_id', '222222223');
              fd.append('third_id', 4);
              return fd
            }
        },
        revert: null,
        restore: null,
        load: null,
        fetch: null
    }
});

Shows "Error during upload" But should be an "Upload complete" Because its upload to the server with no problem, like its complete.