I'm desperately trying to implement Google AdMob 5.4 in Unity to run on iOS 14. It is working fine on Android but on iOS I can only display test ads and it fails to show real rewarded video ads in the production release. Debugging in Xcode gives me the following log message which gets printed after closing a test ad:

Error acquiring assertion: <Error Domain=RBSAssertionErrorDomain Code=3 "Target is not running or required target entitlement is missing" UserInfo={RBSAssertionAttribute=<RBSDomainAttribute| domain:"com.apple.webkit" name:"Suspended" sourceEnvironment:"(null)">, NSLocalizedFailureReason=Target is not running or required target entitlement is missing}>

[ProcessSuspension] 0x1167b9600 - ProcessAssertion: Failed to acquire RBS Suspended assertion 'WebProcess Suspended Assertion' for process with PID 29188, error: Error Domain=RBSAssertionErrorDomain Code=3 "Target is not running or required target entitlement is missing" UserInfo={RBSAssertionAttribute=<RBSDomainAttribute| domain:"com.apple.webkit" name:"Suspended" sourceEnvironment:"(null)">, NSLocalizedFailureReason=Target is not running or required target entitlement is missing}

Could not signal service com.apple.WebKit.WebContent: 113: Could not find specified service

I use pod to install the AdMob dependencies and I also tried adding the SKAdNetworkIdentifier manually, as described in the AdMob iOS Documentation. Even after adding the NSUserTrackingUsageDescription key for iOS 14 I could not fix the problem.

Does anyone have an idea of what I am missing?

Any help at all would be greatly appreciated. Please let me know if you need more information.