Office 365 power point file won't import

Hello Folks,

I'm using Captivate 2019 and Office 365.  I've created 2 ppt files (ext pptx) and when I try to import them, I receive a message that says "Unable to import Microsoft PowerPoint presentation.  The file may be damaged." 

Any ideas how I can correct this problem? Do I need to save as a ppt file instead?  

Thanks,

Carl S.