Do you use TouchOSC ? Have you implemented the template from RME ?

I use Lemur by Liine

Additional tipps:

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1)

You can predefine the bus for your controller by editing the workspace file (*.tmws)
If you search for "OscRemote":

        <OscRemote0>
            <val e="OscSelBus" v="x"/> 

Here you can edit x with values 0-2 (0=InputBus, 1=PlaybackBus, 2=OutputBus) for OscRemote0-3.
So, after saving, you have assigned the default bus for each controller in your workspace file.

And the controller is mapped to the corresponding bus after fte workspace is loaded in TMFX.

So, no need to switch the bus manually (if you need a kind of fixed environment) after your Tablet/Phone is connected.

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2)

If you look into the OSC description:
https://www.rme-audio.de/downloads/osc_ … ix_new.zip

And if you want to control the "per channel" details on page 2 like fx, stereo, etc...

1. command) "/2/busInput 1" or "/2/busPlayback 1" or "/2/busOutput 1" (selects the bus for page 2)
2. command) "/setBankStart x" or "/setOffsetInBank x" (depends on your situation - selects a single channel for Page 2, x is a number)
3. command) "/2/<YourParam> <Value> (now you can control each parameter and its value)