Hello there,
To test ads unit Ids and to make sure that your implementation of the SDK in your app is correct, you would have to make sure that you enable test device while testing. When you enable test mode and test your Ad unit Ids with our sample apps , you will see a production looking ad with a "Test Ad" label and that confirms that your Ad unit Ids are working. That said, the Ad unit Ids with Test Ad label are safe to click and those will not be counted as invalid clicks from the publishers. if you still notice any invalid activity on your account, you may refer to these following articles on how to prevent invalid activity:
That said, can you please share your Ad unit Id, complete device logs and your app link(if it is live) using "Reply privately to Author" option so that we can test it on our end?
Regards,
Deepika Uragayala
Mobile Ads SDK Team