It seems the "direction" of the RTS-1 affects how the part detects the available resources/capacities. In the testbed below, the right RTS is set to the docked mode and the left one is used to transfer the resources. For some reason, the part sees Monopropellant and electricity from the landing can, but doesn't see its LOX reserve.

(Apologies for non-English locale)

Hi @ihsoft
I'm new on this project, but my question is
How the landing can can transfer monopropellant or electricity to a Oxidizer/Liquid tank?

Is it possible???

@HaullyGames No, it's not possible. The source and target tank types must be the same. In scope of this specific issue, it was said "RTS can see monopropellant ", which is not the same as "can transfer monopropellant".