File Transfers unreliable

Teamviewer 15, all systems.

One Mac, two Windows 10 systems.  The Mac, is mine, one Windows system is mine, the other belongs to a friend.

I need to transfer a large ZIP file from her computer to my Mac.  Teamviewer will not let me.

I tested the procedure using a Windows 10 desktop belonging to me, and it worked.

This is what I notieced...  I've uploaded 2 screenshots from testing with my Windows 10 system as the remote computer.  Before selecting the file, the Receive  and I guess it's an arrow,  are greyed out.  (Below)

After selecting a file, Receive and the arrow are no longer greyed out.  (Below)

Click on the arrow, and the file transfers to my Mac.

When I connect to my friend's W10 system, and select the ZIP file,  the arrow and Receive remain greyed out.

Why?  It is a large ZIP file, can it be too large?