One Signal error

Hello

Added Ona Signal to the application. I use the free version.

When I start the application, I get a black window with the message:

error getting google id id resolution / google / android / gms / ads / identifier /

AdvertisingIdClient; java.lang.NoClassDefFoundError: Failed resolution of: Lcom / google / android / gms / ads / identifier / AdvertisingClient;

at

com.onesignal.AdvertisingIdProviderGPS.getIdentifier (AdvertisingIdProviderGPS.java:45)

at

com.onesignal.Onesignal.registerUserTask (OneSignal.java:1216)

at

com.onesignal.OneSignal.access $ 2300 (OneSignal.java:80)

at com.onesignal.OneSignal $ 7.run (OneSignal.java:1199)

at

java.lang.Thread.run (Thread.java:818)

Caused by:

java.lang.ClassNotFoundException: Didn’t find class

“com.google.android.gms.ads.identifier.AdvertisingClient” on

path: DexPathList [[zip file “/data/app/Test-base.apk”[,nativeLibraryDirectories=[/data/app/Test-app/lib/arm, / vendor / lib /, / system / lib /]]

dalvik.system.BaseDexClassLoader.findClss (BaseDexClassLoader.java:56)

What could be the problem?