ERROR: win32exception: System cannot find file specified

I added Google Mobile Ads plugin to my Unity Project and now it throws this error every couple of seconds. Android dependencies are resolved successfully. I can't find the solution. Also, I had Google Play Games Services added before AdMob integration.

I cannot build my game because of this. The build completes but the file is not prepared. I'm running Unity 2018.1Of2 .

I did change the code of PListProcessor (Assets\GoogleMobileAds\Editor\PListProcessor.cs). It was throwing an error regarding use of Unity.iOS.XCode while I am building an android game on a windows machine. I removed the line and the error was removed.

 Win32Exception: The system cannot find the file specified.
 
 System.Diagnostics.Process.Start_shell (System.Diagnostics.ProcessStartInfo startInfo, System.Diagnostics.Process process)
 System.Diagnostics.Process.Start_common (System.Diagnostics.ProcessStartInfo startInfo, System.Diagnostics.Process process)
 System.Diagnostics.Process.Start ()
 (wrapper remoting-invoke-with-check) System.Diagnostics.Process:Start ()
 UnityEditor.Android.ADB.StartServer (UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit)
 UnityEditor.Android.ADB.Run (System.String[] command, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg)
 UnityEditor.Android.AndroidDeploymentTargetsExtension.GetKnownTargets (UnityEditor.ProgressHandler progressHandler)
 UnityEditor.DeploymentTargets.DeploymentTargetManager.GetKnownTargets (BuildTargetGroup targetGroup, BuildTarget buildTarget) (at C:/buildslave/unity/build/Editor/Mono/DeploymentTargets/DeploymentTargetManager.cs:58)
 UnityEditor.Android.AndroidBuildWindowExtension+<SpawnFetchTargetsThread>c__AnonStorey0.<>m__0 ()
 UnityEditor.Android.<SpawnFetchTargetsThread>c__AnonStorey0:<>m__0()

Your help will be really appreciated. My project is complete and I cannot build it.