Cannot download Dataflash logs in MissionPlanner

I am trying to download my logfiles from the cube.
When I select Download Dataflash Log per Mavlink I am getting the following error in MP:

I am on MP 1.3.75 Build 1.3.7883.26333 and Arducopter 4.0.7

Edit: I downloaded and installed MP beta 1.3.75 Build 1.3.7905.18872 in the meantime with the same error as result.

Are you directly connected with a cable or via a telemetry radio?

directly connected with USB cable. All other actions from MP with the drone work well.

I’ve run into this a couple of times as well. For me it’s usually been because I was impatient and opened up the download screen even though parameters were still being downloaded. I’ve found that if I disconnected, unplug the USB, and try again right away it works.