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Make sure your flash player is up to date.
First head here: http://www.refreshyourcache.com/en/home/ and to refresh your cache. Sometimes browser caching causes problems.
Try in a private window in your browser of choice (e.g. Chrome's Incognito Mode, or Firefox's Private Window). This opens a fresh browser window without any extensions or settings blocking your content.
Try on a different browser (Chrome, Firefox, Edge, Safari, IE, Opera, etc). Sometimes the installation of your browser may be damaged. If it works on every browser but one, reinstall that browser.
Try on a different device or computer (mobile phone, tablet, PC/Mac laptop/desktop, etc.). Sometimes a certain device has trouble with a content type. This is rare but could be a problem.
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