Unable to convert classes into dex format.See the console for details

I add unity adds when i try to build my project i get this error (see title)
my consloe have this messages


CommandInvokationFailure: Unable to convert classes into dex format.
D:\Program Files\Unity\Editor\Data\PlaybackEngines\AndroidPlayer/Tools\OpenJDK\Windows\bin\java.exe -Xmx4096M -Dcom.android.sdkmanager.toolsdir="C:\Users\origi\AppData\Local\Android\sdk\tools" -Dfile.encoding=UTF8 -jar "D:\Program Files\Unity\Editor\Data\PlaybackEngines\AndroidPlayer/Tools\sdktools.jar" -


Build completed with a result of 'Failed'
UnityEngine.GUIUtilityrocessEvent(Int32, IntPtr)


UnityEditor.BuildPlayerWindow+BuildMethodException: 2 errors
at UnityEditor.BuildPlayerWindow+DefaultBuildMethods.BuildPlayer (UnityEditor.BuildPlayerOptions options) [0x00234] in C:\buildslave\unity\build\Editor\Mono\BuildPlayerWindowBuildMethods.cs:191
at UnityEditor.BuildPlayerWindow.CallBuildMethods (System.Boolean askForBuildLocation, UnityEditor.BuildOptions defaultBuildOptions) [0x0007f] in C:\buildslave\unity\build\Editor\Mono\BuildPlayerWindowBuildMethods.cs:97
UnityEngine.GUIUtilityrocessEvent(Int32, IntPtr)

if i go to services/Ads/advanced and disable built-in Ads extension my build have no erros so im wondering

it is fine to build my game with disable built-in Ads extension ?

if yes it is fine
What actually built-in ads extension mean ?

if no it is not fine
What should i do?

Thank you all for your time!