Admob crashing my app at the beginning of launch

I decided to install Admob. However, after installing the Mobile Ads Unity plugin, the application starts and stops working at the beginning of launch. I’ve tried multiple solutions. One of them I added the following codes to AndroidManifest:

 <uses-library android:required="false" android:name="org.apache.http.legacy"/>  
 android:value="[ADMOB APPLICATION ID]"/> //I changed only this ID. I put there my admob id.

But this did not work. I’ve been through this for a long time. Can you please help? With my all respect …

AdMob manager might be the problem. Unselect the AdMob manager and select Google AdMob.