xplane could not apply the "DREF" message

[AdoreMoney]

I installed XPLANE on steam, and it's xplane 11.55 version

[JDatPNW]

Hello,
as far as I know XPlane 10 and XPlane 11 are 2 differently sold games on steam.
I have never used or tested XPlane 11, so I can not tell you whether or not it is compatible with QPlane. If you want to make things easier on yourself, then I would recommend XPlane 10, as it would be more straightforward to simply use that. If you want to stick with XPlane 11, then you would have to figure out how to interface with it, since I don't know how compatible XPlaneConnect is with that version. XPlaneConnect does mention XPlane 11 on their GitHub, so it should work to some extend, but I can not tell you how.
Hope this helps,
David