Submission not working

[the-can-of-soup]

I tried to fill out the submission form, but after I clicked the final "Upload Promotion" button, the loading animation popped up, then disappeared, but the button was still grayed out and the console had an error. I retried several times by refreshing the page and re-filling out the form.

I use Firefox, so maybe that's the problem?

Here's a screenshot of the console: