Kutools multi-select drop down in an excel file

I inserted several Kutools multi-select drop down selections into an excel Office 365 Excel file. I sent it to two user that don't have a Kutools for Excel license. They indicated only one selection could be made. I inquired about this before purchasing the license, and was told a user could use the file as setup by me using Kutools for Excel and the function would appear and could be as designed. Neither user has the ability to do multi-selections. What is the problem?