I just installed this extension & get this error in Chrome console

Uncaught TypeError: Cannot read property 'length' of undefined
    at YTF._this.getData (script.js?v=4.5.7:1239)
    at new YTF (script.js?v=4.5.7:1744)
    at HTMLDocument. ((index):196)
    at u (jquery.min.js?b27c1c03654441b58416085d41704f5e:2)
    at Object.fireWith [as resolveWith] (jquery.min.js?b27c1c03654441b58416085d41704f5e:2)
    at Function.ready (jquery.min.js?b27c1c03654441b58416085d41704f5e:2)
    at HTMLDocument._ (jquery.min.js?b27c1c03654441b58416085d41704f5e:2)


I have tried using videos & playlists.
I have added Google API and authorised the site (although still in maintenance mode)
I Have assigned the domain to my subscription here.

Have I missed something or is this a bug?