Facebook proof fails

I am unable to prove my Facebook account with Keybase. I have tried the Mac app as well as the CLI tool, with the same result. The page opens from the provided link and shows that I'm constructing a post with the Keybase info attached, and sharing is set to Public. But when I submit the post Facebook comes back with a Page Not Found error:


When I go to my news feed the post is still there, but keybase can't find it.


`> keybase prove facebook`
`Your username on Facebook: clayfiske`
`Please follow this link and make a public Facebook post.`
`The text can be whatever you want, but the post must be public.`

`https://facebook.com/v2.9/dialog/oauth?client_id=270998186616745&display=popup&response_type=code&scope=user_posts&redirect_uri=https%3A%2F%2Fkeybase.io%2F_%2Ffacebook_login_redirect%3Fsig_id_med%3DTj9fBS0G1VD21UreoBxYQ7JZX4ar1jDfykbslruGHv0%26keybase_token%3DlgHZIDlkOWIzMmQxYTk0ZWY2ZjM1ZjZhNWJjZTA2N2RiMTE5zlneaO3OAAP0gMDEIBlG%252FheqPo3EDbvChrgb58K4p7mqpESPr2Lzpdu2l6Gn`

`Check Facebook now? [Y/n]`
`Couldn't find posted proof.`
`Check Facebook again now? [Y/n]`
`Couldn't find posted proof.`

This happens whether I'm already logged into Facebook in advance or not.

`> keybase version`
`Client: 1.0.33-20171003193446+d9ceb86ac`
`Service: 1.0.33-20171003193446+d9ceb86ac`

I have successfully proofed both GitHub and Twitter, just not Facebook.

Start by reproducing `keybase prove facebook` with the reported Facebook flow, using the supplied version and comparing the CLI and Mac app behavior. Inspect the Facebook proof path and its response handling; done means a public post is found and the proof completes successfully, or the issue is narrowed to a changed external flow.

Written by the indexing model from the issue text.