TOPIC:

My 8x12 stopped sound output while device/GUI seem ok & show signal activity when playing sound. 
Am I missing sth or ist it defective (bought 2018)? 

Use case: 
I use an 8x12 (v2) w/o Dirac  as a crossover for my DIY 4 way active speakers (to enable room correction via the 8x12 DSP). The AVR does then the final setup, including my stere system & other spekaers for surround.  
So we look here only at the  R/L for stereo music which is also used for home cinema (Auro 3D) 
My front system (R/L Speakers) are a 15'' sub module each + very compact 3way top unit (8'' low mid, 2'' mid dome, 1'' tw dome)= 4ch each. 

Setup is:
1) Param set 1: Analogue, for record player & home cinema without having to use the DSP volume remote:
AVR Denon 4100 (Auro 3D setup with height speakers) --> Analoge pre-out (L, R, Sub 1, Sub2  to Input ch 1,2,3,4) --> output ch 1,2,3,4 (to left), 5,6,7,8 (to right ) --> cinch to jack cables --> Behringer DI box for symmetric signal -> XLR to XLR --> 2x 4 ch PA amps -> Speakon cables to Chassis/Shakers
2) Digital for BR/DVD audio (less loss due to vol control BEFORE DSP): AVR -> HDMI 3 out (=zone 2)-> breakout box (HDMI Video/audio splitter; there's no dig audio out on the denon) -> SPDIF out -> 8x12 SPDIF in -> output as above (for digital audio)

In the 8x12, No input is muted, DSP is NOT muted, routing table has 0db at all channels.
Initial config (after 1st room correction, did definitla work) re-loaded - no effect 

1) Device seems ok, Connect ok, GUI ok, Input/output show signal activity
FAIL: NO output at any port !! worked fine before, then stopped. I checked with an active studio speaker (Yamaha LS-7) --> ok when directly at AVR analogoue pre-out, silent at any 8x12 cinch output

2) Device ok, GUI ok, NO signal shown in GUI on input channels, NO signal in poutput channels. Sometimes (not reproducable), very faint signal heard. In these cases, only with massive gain at all stages (DI box+20db, Input filters +9, AVR gain etc) somnethin can be heard..... 

Is this a possible defect scenario, or is it silly & I am overlooking sth ? 
I remember I did sth with the dip switches to adapt because it was too loud or too silent, but I don't emember what I did then... however it worked fine for years.