2811’s are probably the most commonly used pixel for Wled so you shouldn’t be getting any issues unless there’s a connection problem or the first pixel is dead. The can happen through reverse polarity connecting or possible data line surges through not using an inline resistor however this is rare since the data output is only 3.3v or less.
followed the top diagram, but with no level shifter or resistor. Last night my wifi connectivity was not working for unknown reason… maybe it part of the reason…
so flashed a new ESP8266, wifi connectivity work fine. wled app on iphone was not able to find the LEDs so I typed the IP address and it discovered it.
from the app I am able to turn on and off the ESP but the 2811 LEDs still not turning on.