I am trying to set up a message filter extension that will use shared web credentials for basic auth when calling to its ILMessageFilterExtensionNetworkURL. I have associated domains set up for both "messagefilter:" and "webcredentials:" and the message filter IS correctly calling the ILMessageFilterExtensionNetworkURL with each message - so that part is working. As detailed here, I have set up Shared Web Credentials and my view controller is using SecAddSharedWebCredential() to save the creds to the correct domain. Using Authorization services, the creds are auto-filled into my app's login screen. When I go under Settings > Passwords, I see the creds are saved and they are the correct creds to the corrent website that matches ILMessageFilterExtensionNetworkURL. Regardless of all of this, the deferQueryRequestToNetwork() refuses to use the creds and implement Basic Auth in its URL call. It makes the call to the correct URL, it just won't use the Shared Web Creds for basic auth. Any help would be greatly appreciated.