Please check the Version of Word by going to the Word menu and About Word.
if it is version 16.1 or higher then see the steps at
If it is version 15.41 or lower then see the steps at
If you continue to have trouble then Please contact Technical Support directly
1-800-336-4474 option 4 then 1 or
https://support.clarivate.com/Endnote/s/technicalsupport?language=en_US