graph.facebook.com error: failed curl POST

[isomorphisms]

$ fbcmd auth XXXXX

fbcmd [v2.0-beta2] ERROR: Failed CURL POST:
https://graph.facebook.com/oauth/exchange_sessions
client_id=XXXXXXXXXXXXXXX&client_secret=xxxxxxxxxxxxxxxxxxxxxxx&sessions=4.0.298473028734ac91acf877.0-yYyYYyyyyyy000998yyyY