Can't remove accounts or post using Publicize

I have Jetpack Publicize connected to Twitter and Facebook. It was working for a while, and then it stopped posting a few days ago.

If I create a new post, the publicize option is there, but it doesn’t successfully share the post on Facebook or Twitter.

On the Sharing page it shows both Facebook and Twitter as connected. And if I click the ‘X’ to disconnect, it fails. Instead I see: “You have successfully connected your blog with your Facebook account.” ever after I clicked the disconnect option.

I even tried adding Tumblr which appeared to go through correctly, even showing the “You have successfully…” message. However once I click OK the account is there. It is not connected.

I’m pretty lost on how to troubleshoot this – it claims I am connected to two accounts but doesn’t post anything, and I can’t add further ones. Everytime I just get the “You have successfully…” message but nothing happens.