No 'Access-Control-Allow-Origin' header is present on the requested resource. Apollo Graphql, Koajs

Появилась такая ошибка:

Я добавил frontend через vercel, а backend через heroku. На frontend получаю данные через @apollo/client:

    const createApolloClient = (cache = {}) =>
  new ApolloClient({
    ssrMode: typeof window === "undefined",
    cache: new InMemoryCache().restore(cache),
    link: createUploadLink({ uri: process.env.API_URI,
    credentials: 'include'
  }),
  });
    export const apolloClient = createApolloClient(ApolloCache) 

На backend использую koajs и Apollo Graphql :

const __dirname = path.resolve();
async function startServer() {
  // Ensure the upload directory exists.
  await makeDir(fileURLToPath(UPLOAD_DIRECTORY_URL));

  const corsOptions = {
    origin: process.env.CLIENT,
    // 'http://localhost:3001', 'http://localhost:4000/graphql'],
    credentials: true,
    }

  const app = new Koa()
  const apolloServer = new ApolloServer({ schema });

  await apolloServer.start();

  app
    .use(
      graphqlUploadKoa({
        maxFileSize: 10000000, // 10 MB
        maxFiles: 20,
      })
    )
    .use(serve(path.join(__dirname, '/uploads')))
    // @ts-ignore
    .use(cors(corsOptions))
    .use(apolloServer.getMiddleware({ app, path: "/graphql", cors: false }))
    .listen(process.env.PORT, () => {
      console.info(
        `Serving http://localhost:${process.env.PORT} for ${process.env.NODE_ENV}.`
      );
    });
}

mongoose
  .set('strictQuery', false)
  .connect(process.env.MONGO_DB, {
    useUnifiedTopology: true,
    useNewUrlParser: true
  }).then(() => console.log('?Db ok'))
  .catch((err) => console.log('DB error ❌', err))


startServer();

Помогите пожалуйста, чем может быть вызвана эта ошибка?