Veja este post no Instagram, após o post incorporado do Instagram

[Jagster (Jakke Flemming)]

E você seguiu isto:

Configure an app token for Instagram oneboxes

If you already have a Facebook App associated with your Discourse site, scroll down to Adding oEmbed to your Facebook App. If you do not have a Facebook Developer account and Facebook App: Go to https://developers.facebook.com/. You’ll be prompted to log in to your Facebook account if you aren’t currently logged in. You may be asked to ‘convert’ your Facebook account to a developer account if you haven’t done so previously. You may be asked to verify your account with Facebook by adding a phon…

Pode funcionar. Ou não