I was having this issue, and some of the comments on the plugin page indicate others are having the same issue, of not being able to see the moderator section / moderate comments since the last plugin update (or shortly after) on some of their sites.
I don't know what causes this - HOWEVER this is how I got it to work.
I went into the Settings and completely removed the application ID and saved the settings. Then re-entered it.
That was all.
Weird - but maybe it will help someone else