The tmc connection error means that:
- Your screen is talking to the skr
- The skr can’t talk to the tmc 2209s.
Can you send M115 and see what version the firmware is? It should be something like v510D. If you haven’t flashed the skr, then you need to.
Check that the 12V power is really reaching the drivers with a multimeter (careful, don’t short anything).
You can send M122 from repetier host to get even more info. For example, is it all the drivers that are not talking? Or just one?