What else can I try to fix my abilty to build?

For about a week or more I’ve been totally unable to build any project to android. I’ve moved the project to a new folder, I’ve reinstalled everything from Java JDK to Android SDK to Unity itself. When I attempt to build theres a pop up asking if I want to Update the SDK. I say yes and it tells my it’s unable to update. Then I get this error.

UnityException: Requested minimum Android SDK not installed
Build set to use Minimum SDK of AndroidApiLevel16 but the latest installed SDK on the system is 0.
Please use the Android SDK installation tool to install the minimum required SDK version.

UnityEditor.Android.PostProcessor.CancelPostProcess.AbortBuild (System.String title, System.String message, UnityEditor.Android.CommandInvokationFailure ex)
UnityEditor.Android.PostProcessor.Tasks.CheckAndroidSdk.Execute (UnityEditor.Android.PostProcessor.PostProcessorContext context)
UnityEditor.Android.PostProcessor.PostProcessRunner.RunAllTasks (UnityEditor.Android.PostProcessor.PostProcessorContext context)
UnityEditor.Android.PostProcessAndroidPlayer.PrepareForBuild (BuildOptions options, BuildTarget target)
UnityEditor.Android.AndroidBuildPostprocessor.PrepareForBuild (BuildOptions options, BuildTarget target)
UnityEditor.PostprocessBuildPlayer.PrepareForBuild (BuildOptions options, BuildTargetGroup targetGroup, BuildTarget target) (at C:/buildslave/unity/build/Editor/Mono/BuildPipeline/PostprocessBuildPlayer.cs:97)
UnityEditor.HostView:OnGUI()

hi;
try not updating and click “Continue” see what happen;