Routing external chain effects on wavelab 11 creating feedback loop

hello everyone . i’m trying to setup my external gear for mastering. i watched video on WaveLab channel to setup external effects. but i don’t understand why i get audio feedback loop with a huge reverb effect when i apply the effect and instead of making my file fat, it makes its tiny. my setup is RME Fireface UC/ effects: Focusrite Isa TWO / dbx 1066/ mixer Mackie 1642-vlz3 . my problem is in the routing. the routing i use for doing mastering in Cubase 12 . does not create feedback. but WaveLab does. i don’t know if my explanation is clear.
routing order:
-RME main bus 1/2 to effects chain
-effects chain to mixer channel (with sub out3/4 botton)

been stuggling all day with it i don’t understand what is rwong

Are you using the same stereo path to send to some external FX and monitor?

Normally you might use output 3/4 to send to the external FX, then record back in on 1/2 or 3/4 and then monitor what you’re doing on output 1/2.

Are you using Totalmix? I’ll screenshot my TM setting, it’s different for WL.


As you can see, the chain input is zeroed, both to the main bus and the “chain in” bus. WL can still tap its input, but there’s no feedback.