I also replaced my REST URL with my phone number and I get same error/experience.

I added logging to the ILMessageFilterCapabilitiesQueryHandling and it is not getting called. func handle( _ capabilitiesQueryRequest: ILMessageFilterCapabilitiesQueryRequest, context: ILMessageFilterExtensionContext, completion: @escaping (ILMessageFilterCapabilitiesQueryResponse) -> Void ) { os_log("Handling capabilities query", log: self.logger, type: .debug) let response = ILMessageFilterCapabilitiesQueryResponse() response.transactionalSubActions = [.none] response.promotionalSubActions = [.none] completion(response) } ... }

I have the same issue. What I've worked out so far is that the request is never leaving the device, I hooked up my local api implementation via ngrok and it never gets touched. As far as I've read, you don't need the associated domains nor the aasa settings for ILMessageFilterExtensionNetworkURL. offline works fine, just defer to network. My wild hunch with no proof: I live outside of any cell tower range and go through wifi. Under these circumstances, perhaps iOS doesn't allow the network request to go over wifi.

Same boat! When building my target, I now get Provisioning profile "iOS Team Provisioning Profile: xxx.MessageFilterExtension" doesn't include the com.apple.developer.identitylookup entitlement.