how to fix this probelm?
By the error compiling message, it seems that your IDE setting is for an ESP board. The code provided in the IoT Pet Feeder project, is for the Arduino Uno board, that communicated with the esp8266 as its wifi module.
Switch your setting to the Arduino Uno board in IDE.
it can be compiled now , thanks
how can I do that can you please lead me and guide me
In the Arduino IDE, open the Tools menu and look for Board. That will open a list of boards where you’ll be able to select the correct board for the project and or what you have connected.