I'm trying to run a Simple Exponential Smoothing Forecast using the Real Statistics add-in and every time I try this pops up. Microsoft Office Support sent me here because it involves User Generated Content. Any help is appreciated!
if you are meaning the Add-In from www.real-statistics.com, then, as far as I know, it needs the Excel Solver Add-In installed and active. Excel Options, Category Add-Ins, ensure Add-Ins is selected (normally preselected) from the list in the bottom, click on the button next to the right and activate the Solver Add-In. If the problem persists, I would suggest to contact the Add-In author.