Receiving javascript error when using pop up

Hi,
Plugin looks really great but I’m receiving a java script error when trying to use pop-up:

Uncaught TypeError: Cannot read property 'messages' of undefined
    at (index):1003
(anonymous) @ (index):1003
2VM813:1 Uncaught SyntaxError: Unexpected end of JSON input
    at Function.parse [as parseJSON] (<anonymous>)
    at SGPBPopup.filterPopupLimitationCookie (PopupBuilder.js?ver=3.1.1:456)
    at SGPBPopup.getPopupShowLimitationCookie (PopupBuilder.js?ver=3.1.1:436)
    at SGPBPopup.isSatistfyForShowingLimitation (PopupBuilder.js?ver=3.1.1:423)
    at SGPBPopup.checkCurrentPopupType (PopupBuilder.js?ver=3.1.1:328)
    at SGPBPopup.prepareOpen (PopupBuilder.js?ver=3.1.1:312)
    at PopupBuilder.js?ver=3.1.1:2082

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