What do this error and a warning mean?

I have recently updated to Unity 2018.3.6.f1 and I started getting this error and this warning when I enter player settings. It doesn't really do anything, I am able to build apk and everything works normal so I am wondering what this is?
**1**
Failed getting available Android API levels. Make sure your android sdk tools version is 25 or higher and you have internet connection. System.Threading.ThreadHelper:ThreadStart()
**2**
IndexOutOfRangeException: Index was outside the bounds of the array. UnityEditor.Android.AndroidBuildWindowExtension.GetBuildPlayerWindow () (at <7cbc688ae1af4105929402a46c6a4414>:0) UnityEditor.Android.AndroidBuildWindowExtension.RepaintTargetList () (at <7cbc688ae1af4105929402a46c6a4414>:0) UnityEditor.EditorApplication.Internal_CallUpdateFunctions () (at C:/buildslave/unity/build/Editor/Mono/EditorApplication.cs:200)