API Target Level 31 issue on submitting to Google Play

I am trying to submit my apps to the store and now I receive this message:
“Your app currently targets API level 30 and must target at least API level 31 to ensure it is built on the latest APIs optimized for security and performance. Change your app’s target API level to at least 31. Learn More”

I changed the target level API before and it prompts me to update Android SDK. Then I get this error when I try.

“Exception: Unable to install additional SDK platform. Please run the SDK Manager manually to make sure you have the latest set of tools and the required platforms installed.”

Can I please get an answer? I ask questions then it has been ignored several times.