Captivate 2019 embedded video problems

Good morning!

I have inherited a very large (3.69 GB) captivate project that includes several embedded videos. The client was running it from a USB flash drive, apparently. We cannot host it on our SharePoint site because it is too large and also because it won't run from Chrome or Edge (a larger problem for another post). Additionally, it is training for external partners who do not have access to our intranet or shared drives.

I was able to find a host for it through our Corporate Branding group on their Widen Asset site. So, I converted it to an MP4 and asked them to upload it. My problem is that the embedded video runs for a second, then stops. Any advice? I'm not super techy, so keep it simple, please :). No scary code talk for this girl! 

Thanks in advance!

Mary Saunders