If you have a pop-up blocker enabled in your browser, it can prevent the online training course from launching properly. Try disabling the pop-up blocker in your browser, and relaunching the course. Make sure to relaunch the module from the Online Content Structure page for the course, which displayed when you launched the course initially.
Also, remember that the online course opens in a new tab or window, depending on your browser settings. It is possible that the course is open in another window or tab. Check your taskbar for another open browser window or your main browser tab for another open tab.
If you still can’t open an online course, it is possible there is a larger issue. After trying these tips, if you are still unable to launch your online course, please contact the training department by email or by phone.