404 on custom api routes in Mastra Cloud

import { Mastra } from "@mastra/core/mastra";
import { registerApiRoute } from "@mastra/core/server";

export const mastra = new Mastra({
  server: {
    apiRoutes: [
      registerApiRoute("/tester", {
        method: "GET",
        handler: (c) => {
          console.log("[TESTER ROUTE] Handler called:");
          return c.json({ message: "Custom route", status: "ok" });
        },
      }),
    ],
  },
});