Bug overview description.
Using /post/create.json returns an "unexpected error"

What part(s) of the site page(s) are affected?
The API

What is the expected behavior?
There should be no error

What actual behavior is given instead?
{"success":false,"reason":"Unexpected error (2126e70023223ab967a4f7c1c1d615ab)"}

Time of incident (if applicable).
Today

Can you reproduce the bug every time?
Yes.
The alphanumeric string is different each time, but it's always an "unexpected error".
Also:
status = 500
statusText = Internal Server Error

What steps did you take to replicate this bug?
I used https://e621.net/post/create.json to upload an image, with only these two fields:
{"post[tags]": e621_new_tags, "post[upload_url]": direct_image_link}

(because Help: API says "There are only two mandatory fields: you need to supply the tags, and you need to supply the file, either through a multipart form or through a source URL.")

e621_new_tags = a space-separated list of tags
direct_image_link = a URL

Errors or other messages returned (if any).
See above.

You need to provide a source(even if a blank string) and a rating. They are not optional. I'll update the documentation.

KiraNoot said:
You need to provide a source(even if a blank string) and a rating. They are not optional. I'll update the documentation.

Thanks for the fast reply!
I've added rating and source and now it works.