Doubts to flash NodeMCU + Garden Project

I use this command to a Display Widget in this example sketch…

Blynk.virtualWrite(V3, WiFi.macAddress());

If your phone and router support 5Ghz, then no problem.

But all ESP based devices ONLY use 2.4Ghz, so your router needs to support BOTH at same time in-order to work/share properly across the bands