I just joined the MOTU world for the first time (upgraded from a Focusrite 18i20) and I am loving the device thus far. Everything I hoped!
While my old Focusrite had SPDIF Input and Outputs, the MOTU 8Pre-ES obviously does not; however, it does have ADAT (and ADAT bank A can be changed to TOSLINK). So, I've setup my Axe FX 3 to go from SPDIF coxial to Digital via a small converter I bought on Amazon (https://www.amazon.com/gp/product/B06XC ... UTF8&psc=1, if this helps). However, I'm not picking up any sound from within my DAW (Reaper).
Here is an image of my current routing setup. I'm relative new to this style of routing since the 18i20 had relatively limited capabilities.

So, to sum up:
Axe FX 3 -> SPDIF OUT -> Amazon Converter -> TOSLINK IN of MOTU 8Pre-ES. Currently no sound.
DAW: REAPER
OS: Windows 10.
Thanks for any information you can provide!
Best,
CB