I connected a SHT30 shield to a Wemos D1 mini (one on top of the other) to measure temperatures.
Wemos D1 mini (2.3.0):
SHT30 shield:
It works great but when I added a relay on the top of the stack it doesn't work anymore.
Maybe there are a conflict with their pins. So these are their schematics:
This is the solution that I made but I don't know why this works instead of inserting the relay shield on top of the SHT30 shield: