Smartsheet Merge Add-ons stuck on loading

Hello Team, 

I am trying to use Smartsheet Merge Add-ons to print a Row in a Web Form Layout. 

I have completed the steps but it does not work, Merge Data is stuck on Loading as shown below: 

"Smartsheet Merge will create 1 document in Google Drive.

This may take several minutes depending on the size and complexity of your document, and the number of rows you selected."

Thanks for your help,