Question Unity Build And Run

I have been using the unity engine for a long time. Recently I designed a mobile application and when I am trying to BUILD AND RUN the application an error occurs saying that the JDK is not found. Then I installed JDK version 8 1.8.0 and located it properly. Now the error shows as the SDK is missing while I have already installed the SDK and located the folder correctly. I have tried installing different versions available on the internet but still, the problem occurs. I tried restarting Unity as well restarted by the system but it still doesn't work. The SDK and JDK are updated versions (latest versions) and I am using the unity editor version - 2020.3.36f1.

Can anyone please help...