Firebase Doesn't send push notification

Question

I used to send push notifications with only text messages in them. The payload structure was different at the time, and the function "sendToDevices(token,payload)" was utilized. But now I want to send a push notice to several devices with images in it, thus I'm using the "sendMulticast(payload)" function. It works up to Firebase, which means I can see the console message "push notification send" in the Firebase console, but no notification is sent. Also, I tested the payload in the console and everything seemed to be working.

Old Code and its payload

exports.sendPushNotificationToAllDevices = functions.https.onRequest((request, response) => {
    const domain = request.body.Domain;
    if (typeof domain == "undefined" || domain == null || domain == "") {
        response.status(400).send("Domain is empty.");
        return;
    }
    const url = domain + '/Users';
    admin.database().ref(url).once('value')
        .then(snapshot => {
            let tokens = [];
            let counter = 0;
            const count = snapshot.numChildren();
            
            snapshot.forEach(function (data) {
                counter++;
                const token = data.val().FirebaseToken;
                if (typeof token !== "undefined" && token !== null && token != "") {
                    tokens.push(token);
                }
            });
            let uniqeTokens = [...new Set(tokens)];
            if (uniqeTokens.length > 0) {
                const payload = getNotificationPayload(request);
                console.log(uniqeTokens.length);
                const tokensChunk = chunk(uniqeTokens,999);
            
                tokensChunk.forEach(function(tokens){
                    sendPushNotificationTo(tokens, payload); // sendToDevice() function is used.
                });
            }
        });
    response.status(200).send("sending");
});

Old Payload Structure

return {
        notification: {
            title: notificationTitle,
            body: notificationBody,
            clickAction: clickAction,
            sound: 'default'
        },
        data: notificationData
    };

New Code Structure

exports.sendPushNotificationToAllDevices = functions.https.onRequest((request, response) => {
    const domain = request.body.Domain;
    if (typeof domain == "undefined" || domain == null || domain == "") {
        response.status(400).send("Domain is empty");
        return;
    }
    const url = domain + '/Users';
    admin.database().ref(url).once('value')
        .then(snapshot => {
            let tokens = [];
            let counter = [];
            const count = snapshot.numChildren();
            snapshot.forEach(function (data){
                counter++;
                const token = data.val().FirebaseToken;
                if (typeof token !== "undefined" && token !== null && token != "") {
                    tokens.push(token);
                }
            });
            let uniqueTokens = [...new Set(tokens)];
            if (uniqueTokens.length > 0) {
                var payload = getNotificationPayload(request);
                const tokensChunk = chunk(uniqueTokens, 999);
                tokensChunk.forEach(function(tokens){
                    payload['tokens'] = tokens;
                    sendPushNotificationTo(payload); // sendMulticast() function is used.
                });
            }
        });
    response.status(200).send("Sending");
});

New Payload Structure

let message = {
        notification: {
            title: notificationTitle,
            body: notificationBody,
            clickAction: clickAction,
            sound: 'default',
        },
        data: notificationData,
        android: {
            notification: {
                sound: 'default'
            }
        },
        apns: {
            payload: {
                aps: {
                    'mutable-content': 1,
                    sound:sound,
                }
            }
        }
    };

    if (typeof clickAction === 'string' || clickAction !== "") {
        message["android"]["notification"]["click_action"] = clickAction;
    }
    if (typeof imageUrl === 'string' || imageUrl !== "") {
        message["android"]["notification"]["imageUrl"] = imageUrl;
        message["apns"]["fcm_options"]["image"] = imageUrl;
    }
    return message;

Answer 1

Payload structure was not correct for new function "sendMulticast()".

required payload structrue

let message = {
        notification: {
            title: notificationTitle,
            body: notificationBody,
            // clickAction: clickAction,
            // sound: 'default',
        },
        data: notificationData,
        android: {
            notification: {
                sound: 'default'
            }
        },
        apns: {
            payload: {
                aps: {
                    "mutable-content": 1,
                    sound:'default',
                }
            }
        }
    };

    if (typeof clickAction === 'string' || clickAction !== "") {
        message["android"]["notification"]["click_action"] = clickAction;
    }
    if (typeof imageURL !== "undefined" && imageURL !== null && imageUrl !== "") {
        message["android"]["notification"]["imageUrl"] = imageUrl;
    }
    return message;

ClickAction and Sound is not supported by sendMulticast(), send() etch kind of function