"Something Went Wrong" Error with NextScripts/SNAP

I have used the NextScripts/SNAP plugin for a number of blogs without any problem but one particular blog I have it just won’t work for. It is OK posting to Twitter but will not post to Diigo, Delicious or Stumbleupon.

I have tried deleting the API key and re-creating from scratch but with no luck.

With Diigo for example when I try a test post I just get a message saying “Something went wrong… something went wrong…”

Can anyone help?
Many Thanks