These are the headers I send with my get request to https://oauth.reddit.com/api/morechildren in python, however I get hit with a 403 error each time I try it. In the #code it seems like either the link is incorrect or that I'm not 'allowed' to see it.
('User-Agent', 'python:xxxxx:xxxxx by (by /u/XXXXXXXXXXXX)')
('Authorization', 'bearer <TOKEN>')
('children', <comma seperated list of ID36s for comments>)
('link_id', 't3_<ID36>')
('sort', 'confidence')
('api_type', 'json')
You need to send the parameters in POST form values rather than JSON. Here's some examples.