firebaseMessaging.sendEachForMulticast: app/network-error

Start from the firebaseMessaging.sendEachForMulticast call shown in the issue and reproduce the app/network-error with firebase-admin 13.0.2 in development mode. Compare its behavior with the working send method and inspect the returned response. Done means multicast sends successfully without the HTTP/2 protocol error, or the failure is documented with a confirmed cause and workaround.

export async function pushNotification({
  identifiers,
  body,
  metadata,
  title,
  link,
}: PushMessage) {
  try {
    logger.debug(`Push Notification: ${JSON.stringify(identifiers)}`);

    const userPreIdentifiers = identifiers.users;
    const teamPreIdentifiers = identifiers.teams;

    const userIdentifiers: string[] = [];

    if (userPreIdentifiers === "allUsers") {
      const allUserIdentifiers = await getAllUsersIdentifiers();
      userIdentifiers.push(...allUserIdentifiers);
    } else {
      const userTokens = await getUserIdentifiers({
        userRefs: userPreIdentifiers || [],
      });
      userIdentifiers.push(...(userTokens || []));
    }

    const teamIdentifiers = await getTeamIdentifiers({
      teamRefs: teamPreIdentifiers || [],
    });

    const tokens = [...(userIdentifiers || []), ...(teamIdentifiers || [])];
    logger.debug("All tokens:", tokens);
    if (tokens.length === 0) {
      logger.debug("No tokens found for push notification");
      return;
    }

    const message: MulticastMessage = {
      tokens,
      notification: {
        title,
        body,
      },
      data: metadata as { [key: string]: string },
      ...(link && {
        webpush: {
          fcmOptions: {
            link,
          },
        },
      }),
    };
    const response =
      await firebaseConfig.firebaseMessaging.sendEachForMulticast(message);

    logger.debug(
      `Successfully sent push notification: ${JSON.stringify(response)}`
    );
  } catch (error) {
    logger.error("Error sending push notification:", error);
  }
}

{"responses":[{"success":false,"error":{"code":"app/network-error","message":"Error while making request: Stream closed with error code NGHTTP2_PROTOCOL_ERROR. Error code: ERR_HTTP2_STREAM_ERROR"}}],"successCount":0,"failureCount":1}

I am using the "firebase-admin": "^13.0.2", sdk. The sendEachForMulticast not working on my development mode (did not try yet in production). However, if I am using the send method it will successfully push the notification.