Warpinator - Online then Offline

[wmeler]

I have 2 linux mint machines on the same Wifi Network.
I turned off the Firewalls on both.
I start Warpinator on both.
They see each other. I connect to A on B and B on A.
They both show as "Online" to the other.
File Transfer from A. Accept on B. Starts. Can see file growing.
File Transfer from B. Accept on A. Starts. Can see file growing.

Then...one goes offline. Then another.

This happens *every* time after maybe 30 seconds to a minute at most.

Ideas?

[Cosmo.]

You did not say one word about the versions of Mint and of Warpinator.