If you have problems with AsyncElegantOTA: Other than shown in the video, you need the libraries ESPAsyncTCP and ESPAsyncWebServer from me-no-dev on Github in order to get the OTA update working. You will not find them in the Arduino IDE Library Manager, but you have to download them directly from the Github page and put them in the library folder of the Arduino IDE: https://github.com/me-no-dev/ESPAsyncTCP https://github.com/me-no-dev/ESPAsyncWebServer