Kodi doesn't see zip file or add-on in download folder



I am using Amazon Firestick 4K max and Kodi v21 release version. I need to install a zip file from local storage. The zip file works well if I use Window. Then I transferred the file to firestick and put it ‘download’ folder. File Explorer running on Firestick confirms the file. 

When I click ‘Install from zip file’ for add-on and select ‘download’ folder, Kodi shows no file in that location. I wonder whether the ‘download’ folder seen from Android File Explorer is the same as what Kodi access. 

Can anyone provide insights for this issue?