Looks like the motor gone bad.
Green light is good. Charges good, Front derailleur works fine.
App shows both components. Pressing the button on the derailleur for debugging does not move anything.
Bad motor component is my guess.

I emailed LTWOO direct. Nothing back.
Any other options ?
I'd hate to have to shell out another $600.00 for a whole new V3.0 group set when I all need is damned rear D.
AliEx doesn't seem to sell previous version of parts.

I've fitted these to my gravel bike.

Can't say I have any issues about the quality, they do seem a little grabby with crosswinds but its also my first time using tyres this wide too so that may be the problem.

Now then........ started building the frame for a friend of mine who bought this despite all I told him. Beautiuful looking outside and inside, except. See video below. Waiting to see how he resolves the issue with the seller and AE. The rear went in without the issue, front one not a chance. Trying to push the hose from the bottom or from the top, same result. Stuck in the same spot.

https://drive.google.com/file/d/1oCDvdzx4j5r2-i0NqXFMguxn9N19KMig/view?usp=sharing

A couple of quick thoughts. Yes, 35mm vs. 32mm clearance is like 1-1.5mm difference per side. It’s not that much, but it can make a huge difference if you actually intend to run a 32mm tire on a large IW rim or a 35mm knobby tire. I recognize I might be the only one who has done both, but it was a criteria for me. This was one of the only options, Chinese or not that could clear a 35mm tire with 6mm all the way around and had a race bike’s geo. The Cervelo and Factors options couldnt do that at the time.

Regarding Chinese companies OEMs pumping out replicas or products that are too flexy / not fit for actual use by people who want to go fast on bikes; the irony is that y’all are complaining on a thread about one OEM products that is an original design that was allegedly benchmarked to deflection numbers of the Giant TCR. Yes, this frame has its warts, the OEM part spec is poor, and the rubber bits are total crap or missing; but it builds into a really nice, light, versatile bike if the geo is right for you.

Also for any Newcomers, it is important to remember that this is "His Opinion" and that there mostly positive opinons of TanTan/Seraph frames on this forum.  It should go without saying that you (the perspective buyer) should do your own research before buying any product.