Unable to instantiate mediation adapter class.

[TonyAnine]

onAdFailedToLoad:{ "Code": 3, "Message": "Unable to instantiate mediation adapter class.", "Domain": "com.google.android.gms.ads", "Cause": "null", "Response Info": { "Response ID": "XXX", "Mediation Adapter Class Name": "", "Adapter Responses": [ { "Adapter": "com.google.ads.mediation.facebook.FacebookAdapter", "Latency": 0, "Ad Source Name": "Meta Audience Network", "Ad Source ID": "XXX", "Ad Source Instance Name": "Meta Audience Network", "Ad Source Instance ID": "XXX", "Credentials": { "pubid": "XXX" }, "Ad Error": { "Code": 3, "Message": "Unable to instantiate mediation adapter class.", "Domain": "com.google.android.gms.ads", "Cause": "null" } } ], "Response Extras": { "mediation_group_name": "XXX" } } }