i'm trying to build my android game in unity but they show me a problem "unable to merge android manifests "

Question

CommandInvokationFailure: Unable to merge android manifests. See the Console for more details. 
C:\Program Files\Java\jdk1.7.0_55\bin\java.exe -Xmx2048M -Dcom.android.sdkmanager.toolsdir="C:/Users/ADEL/AppData/Local/Android/sdk1\tools" -Dfile.encoding=UTF8 -jar "C:\Program Files\Unity\Editor\Data\PlaybackEngines\AndroidPlayer/Tools\sdktools.jar" -

stderr[

]
stdout
Warning: [Temp\StagingArea\AndroidManifest-main.xml:12, C:\Users\ADEL\Documents\2\Temp\StagingArea\android-libraries\UnityAds\AndroidManifest.xml:3] Main manifest has <uses-sdk android:targetSdkVersion='25'> but library uses targetSdkVersion='26'
]
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()

Answer 1

Your Unity Ads AndroidManifest.xml has 'targetSdkVersion' = 26, but your Main AndroidManifest.xml (it should be in Assets/Plugins/Android) targetSdkVersion is set to 25.

While processing Android build Unity is collecting all libs AndroidManifest's and tries to merge it, that`s why You've got this error.

You should to update targetSdkVersion in your Main AndroidManifest.xml