I keep on having the same problem (it has worked fine before). And unfortunately no response receievd yet. So I really would appreciate it if and when someone has a solution.
FYI: I have de- and reinstalled the plugin, have the proper keys, and performed all other steps again.
same problem here – I have donated via PayPal to the developer before, but that does not guarantee the continuance of the plugin either. Posts of March 5 and after (more recent) do not show. Any suggestion will be appreciated!