The yellow blinking light of the Apple router indicates that you need to update the firmware or a base station has been reset. Update the firmware of your router to fix Apple Airport flashing yellow light. If you still find the error, follow the steps mentioned below to reset the base station.
Steps to resolve flashing yellow light:
Switch on your Mac and make sure it is connected to the Airport.
Now, click on the Wi-Fi icon.
Then, open the Airport utility application.
Check the name of the base station.
Follow the onscreen process to setup the network properly.