I have this function to fetch JSON data from a URL

   func fetch<T: Decodable>(_ url: URL, defaultValue:T, completion: @escaping (T) -> Void) {
        let decoder = JSONDecoder()
        URLSession.shared.dataTaskPublisher(for: url)
            .retry(1)
            .map(\.data)
             .decode(type: T.self, decoder: decoder)
           .replaceError(with: defaultValue)
            .receive(on: DispatchQueue.main)
            .sink(receiveCompletion: { (error) in
                print("fetch failed: \(String(describing: error))")
            }, receiveValue: completion
            )
            .store(in: &requests)
    }

This code has worked fine before when run against other web sites. When I run it against a new URL I get no data back and this message

2020-09-26 12:11:25.698193+0100 GameDetails[5624:453013] [] nw_protocol_get_quic_image_block_invoke dlopen libquic failed fetch failed: finished

The URL I am trying is: https://api.boardgameatlas.com/api/search?&client_id=JLBr5npPhV

I'm wondering what the error "finished" means, anyone got any ideas or something else I can try?