In the event that the sidebar UI element in Excel gets stuck (appears blank or seems to stay in a loading state forever), you can use the following methods to reset the application cache, based on your version of Excel.
Excel Desktop for Mac
In the Mac version of Excel, there should be an information icon in the corner of the sidebar UI:
Click on this to get the menu and then select Clear Web Cache. (Note that this option is only available in Excel for Mac.)
Wait a few moments, and from the same menu, select Reload.
Excel Desktop for Windows
Clearing the application cache in the Windows version of Excel requires usage of Microsoft Office's Upload Center.
First, log out by removing logins from the Team Management site using these steps: Removing a Login (Log Out)
Next, find and open the Upload Center using these steps: Microsoft Office Upload Center
Once that is open, you can clear the cache from the Upload Center.
From here, go ahead and sign back in to Supermetrics through the Excel add-in.
It is possible that you may get the 'No queries found' error after completing the steps above. In order to fix this error, follow the instructions in the 'No queries found' error in Excel support article.
In most cases, reloading the frame of the sidebar element will fix the issues with it. The exact steps will depend on your browser, but generally right-clicking in the sidebar and selecting "Reload Frame" from the menu will do it.
For example, the option as seen in the Chrome browser:
If this does not help, you then need to clear the application cache via the developer tools/browser settings. The exact steps to do this will depend on the browser. Then reopen the Supermetrics sidebar.
Example in Chrome browser, you would need to open the developer tools, go to Application and clear these settings: