unable to merge android manifests

When building my game for android it's giving me this error every time

CommandInvokationFailure: Unable to merge android manifests. See the Console for more details. C:\Program Files\Java\jdk1.8.0_45\bin\java.exe -Xmx2048M -Dcom.android.sdkmanager.toolsdir="C:/Users/U/AppData/Local/Android/sdk\tools" -Dfile.encoding=UTF8 -jar "C:\Program Files\Unity 5\Editor\Data\PlaybackEngines\AndroidPlayer/Tools\sdktools.jar" -

stderr[

] stdout[ Warning: [Temp\StagingArea\AndroidManifest-main.xml:12, C:\Users\U\Documents\repos\Unity\Color Tap\Color Tap\Temp\StagingArea\android-libraries\unity-ads\AndroidManifest.xml:3] Main manifest has but library uses targetSdkVersion='23' ] exit code: 1 UnityEditor.Android.Command.Run (System.Diagnostics.ProcessStartInfo psi, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg) UnityEditor.Android.AndroidSDKTools.RunCommandInternal (System.String javaExe, System.String sdkToolsDir, System.String[] sdkToolCommand, Int32 memoryMB, System.String workingdir, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg) UnityEditor.Android.AndroidSDKTools.RunCommandSafe (System.String javaExe, System.String sdkToolsDir, System.String[] sdkToolCommand, Int32 memoryMB, System.String workingdir, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg) UnityEditor.HostView:OnGUI()

This error only started to happen after i integrated unity ads in my project, i'm able to fix it by changing my minimumAPI level to 6 but i want my game to run on older android versions so is there any other solution?
Thank you for your help!