Having issue building apk

Hello, semi-newish to this and don't understand how this error came about. I was able to build the apk properly a few weeks ago, no problems, but I took a break and when I came back to it today, I am unable to build the apk and I'm getting this new error.

 CommandInvokationFailure: Failed to re-package resources. C:\Users\MYNAME\AppData\Local\Android\sdk\build-tools\27.0.0\aapt.exe package --auto-add-overlay -v -f -m -J "gen" -M "AndroidManifest.xml" -S "res" -I "C:/Users/MYNAME/AppData/Local/Android/sdk\platforms\android-23\android.jar"
 -F bin/resources.ap_
 
 stderr[ AndroidManifest.xml:5: error: Error: String types not allowed (at 'configChanges' with value 'mcc|mnc|locale|touchscreen|keyboard|keyboardHidden|navigation|orientation|screenLayout|uiMode|screenSize|smallestScreenSize|fontScale|layoutDirection|density').
 
 ] stdout[ Configurations:  (default)  v14  v21  mdpi-v4  xhdpi-v4
 
 Files:   drawable\app_banner.png
     Src: (xhdpi-v4) res\drawable-xhdpi\app_banner.png   drawable\app_icon.png
     Src: (mdpi-v4) res\drawable-mdpi\app_icon.png   values\strings.xml
     Src: () res\values\strings.xml   values\styles.xml
     Src: () res\values\styles.xml
     Src: (v14) res\values-v14\styles.xml
     Src: (v21) res\values-v21\styles.xml   AndroidManifest.xml
     Src: () AndroidManifest.xml
 
 Resource Dirs:   Type drawable
     drawable\app_banner.png
       Src: (xhdpi-v4) res\drawable-xhdpi\app_banner.png
     drawable\app_icon.png
       Src: (mdpi-v4) res\drawable-mdpi\app_icon.png   Type values
     values\strings.xml
       Src: () res\values\strings.xml
     values\styles.xml
       Src: () res\values\styles.xml
       Src: (v14) res\values-v14\styles.xml
       Src: (v21) res\values-v21\styles.xml Including resources from package: C:\Users\MYNAME\AppData\Local\Android\sdk\platforms\android-23\android.jar applyFileOverlay for drawable applyFileOverlay for layout applyFileOverlay for anim applyFileOverlay for animator applyFileOverlay for interpolator applyFileOverlay for transition applyFileOverlay for xml applyFileOverlay for raw applyFileOverlay for color applyFileOverlay for menu applyFileOverlay for font applyFileOverlay for mipmap Processing image: res\drawable-xhdpi\app_banner.png Processing image: res\drawable-mdpi\app_icon.png
     (processed image res\drawable-mdpi\app_icon.png: 90% size of source)
     (processed image res\drawable-xhdpi\app_banner.png: 93% size of source)
     (new resource id app_banner from xhdpi-v4\drawable\app_banner.png
 #generated)
     (new resource id app_icon from mdpi-v4\drawable\app_icon.png
 #generated) ] exit code: 1 UnityEditor.Android.Command.WaitForProgramToRun (UnityEditor.Utils.Program p, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg) UnityEditor.Android.Command.Run (System.Diagnostics.ProcessStartInfo psi, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg) UnityEditor.Android.PostProcessor.Tasks.TasksCommon.Exec (System.String command, System.String args, System.String workingdir, System.String errorMsg) UnityEditor.Android.PostProcessor.Tasks.BuildResources.CompileResources (UnityEditor.Android.PostProcessor.PostProcessorContext context) UnityEditor.Android.PostProcessor.Tasks.BuildResources.Execute (UnityEditor.Android.PostProcessor.PostProcessorContext context) UnityEditor.Android.PostProcessor.PostProcessRunner.RunAllTasks (UnityEditor.Android.PostProcessor.PostProcessorContext context) UnityEditor.BuildPlayerWindow:BuildPlayerAndRun()

I have NDK and SDK setup properly, and I was able to build the apk a few weeks ago. I have no idea what happened. :\