iOS Message Filter Extension - deferQueryRequestToNetwork(completion:) error I made a test app using the iOS App template and added a target using the Message Filter Extension template which invokes deferQueryRequestToNetwork(completion:) when receiving an SMS. The app and the extension have same "Associated Domains Capabilities" with "messagefilter" pointing to a server which receives query requests and returns proper responses. The extension has the "ILMessageFilterExtensionNetworkURL" key in Info.plist file which specifies the server URL. deferQueryRequestToNetwork(completion:) throws a com.apple.calls.messagefilter error which reads "Extension's containing app (appID ) unauthorized to defer requests to host "