Cannot send message with FCM

Hi AppWrite, I created a function from your templace (FCM template). I tried to send a message but I cannot go any further than getting an error 500 {"ok":false,"error":"Failed to send the message"}.

This is the curl request.

curl -X POST https://XXXXXXXXXXXX.appwrite.global \
-H "Content-Type: application/json" \
-d '{"deviceToken":"XXXXXXXXXX", "message": {
        "title": "Title",
        "body": "Hello World"}}'

Not sure if the problem is related with the the deviceToken or the settings of the function (FCM_CLIENT_EMAIL, FCM_DATABASE_URL, FCM_PROJECT_ID or FCM_PRIVATE_KEY)

I believe it is the later because I am using the deviceToken with the functions of firebase and I can perfectly receive messages. This is the code I use to send messages in directly in Firebase

return admin.messaging().sendToDevice(token, payload)
  .then(response => {
          console.log("Successfully sent message: ", response);
          return null
          })
          .catch(response => {
          console.log("Error sending message:", error);
          return null
        });

Hope someone that has it working can help me

Thank you for your time in advance

Did you have created a token/key in the firebase dashboard and have set it?

I went to service accounts, in project settings, Firebase Admin SDK->Generate new private key. Do you mean that? For FCM_PRIVATE_KEY I used the value private_key_id in the json generated as the other (private_key) starts with "-----BEGIN PRIVATE KEY-----\nMIIE....Z0ATl5yuc\n-----END PRIVATE KEY-----\n" and does not look similar to the one in the github readme.md

I have tried with the private_key in case was that but still the same error. All the values FCM_CLIENT_EMAIL, FCM_DATABASE_URL, FCM_PROJECT_ID or FCM_PRIVATE_KEY are from the json except for the FCM_DATABASE_URL which I pick from the Project settings>Firebase Admin SDK inside the bracket admin.initializeApp({...}