Mission PLanner wont connect to my SpeedyBee F405 Stack

So I am new to Ardupilot, leaving Betaflight behind.

Loaded Mission Planner and have a brand new SpeedyBee 405 Stack ready to go.

Connected once to Install firmware, follow instructions and disconnected USB cable, but now it wont connect again. Says MavLink Timeout?

Also at the end says No Heart Beat Signal Detected.

I was able to load the .hex file firmware via INAV by placing the FC into DFU mode. Once flashed, it then uses the ST Virtual COM port. However, if you disconnect the cable, you loose the connection and the Virtual COM port dissapears.

So something to do with the Ardupilot Firmware?

Cheers!
J

Im having the exact same problem but woth a speedybee f405 wing fc did u find a fix?