tried above, it is not working. My co-worker experience the same problem.

I saw below also /Applications/SimpleFirewall.app/Contents/Library/SystemExtensions/com.example.apple-samplecode.SimpleFirewallML4HRHFY98.SimpleFirewallExtension.systemextension: entitlement com.apple.developer.endpoint-security.client not present or not true debug 09:11:21.169301-0800 SimpleFirewall failed to fetch /Applications/SimpleFirewall.app/Contents/Library/SystemExtensions/com.example.apple-samplecode.SimpleFirewallML4HRHFY98.SimpleFirewallExtension.systemextension/Contents/_CodeSignature/CodeRequirements-1 error=-10 debug 09:11:21.169342-0800 SimpleFirewall SecStaticCode network default: YES debug 09:11:21.169404-0800 SimpleFirewall close(16) err: 0 default 09:11:21.169770-0800 SimpleFirewall Saving configuration SimpleFirewall with existing signature (null) when I debug the code, both below are called NEProvider.startSystemExtensionMode() IPCConnection.shared.startListener() Starting XPC listener was called. The App registered was called. Strange thing is that FilterDataProvider init was not called.

I still have issue. it looks like FilterDataProvider init was never called. I attached the log for extension and firewall app. extension.log firewall1.log firewall2.log