I dont't understand button (Try to control the sg90 servo motor through the nodemcu)

Don’t use delays, or other blocking code (like for() loops)… especially in the void loop() or even in sub-functions directly called from the void loop().

http://help.blynk.cc/getting-started-library-auth-token-code-examples/blynk-basics/keep-your-void-loop-clean

Look at other timing options with servos…

Her is a couple I have made…