Generate build with exp build:ios (tried with -c).
Try to deploy it to the testflight and get an error in Application Loader:
ERROR ITMS-90046: "Invalid Code Signing Entitlements. Your application bundle's signature contains code signing entitlements that are not supported on iOS. Specifically, value 'dns-proxy' for key 'com.apple.developer.networking.networkextension' in 'Payload/Exponent.app/Exponent' is not supported."
Had tried using new certificates, not helped.