MP: No heartbeat packets received. QGroundControl connects fine

As title, in MP I get this error when connecting:

“No heartbeat packets received.”

I don’t understand what is going wrong because QGroundControl connects fine though and shows heartbeat packets arriving in Mavlink Inspector.

I have a wired USB connection to an “official” Pixhawk1 with latest Arducopter firmware 4.0.5. I have tried the exact same setup with 2 other Pixhawk1 autopilots, this time they are clones, and they connect fine to QGC and MP without any problems.

For clarification, I am using native QGC on Linux and MP on Windows.

I don’t know if it is relevant, but the Pixhawk clones come up as COM4 in Windows, and the official Pixhawk appears as COM8.

Please could someone help me out? Thanks.

I fixed this after much faffing.

Turns out I needed the “Holybro Pixhawk driver”. This is not the same as whatever other driver I had installed. #windowsproblems