A Unity ID allows you to buy and/or subscribe to Unity products and services, shop in the Asset Store and participate in the Unity community.
Separate names with a comma.
Please install the "AppCoins BDS Wallet" (https://play.google.com/store/apps/details?id=com.appcoins.wallet&hl=en_US)and have another try.
UnityAds is individual package, so if you got compile error, just delete it from the Asset folder. Server side integration is optional.