Failed to parse Dialogflow response into AppResponse because of invalid platform response (with Youtube API) - dialogflow-es

Question

I am trying to build a YouTube entertainment app using Google Assistant, following this tutorial: here. I have followed every step precisely, copying code verbatim, but when I run the test, I get this error:
MalformedResponse Failed to parse Dialogflow response into AppResponse because of invalid platform response: Could not find a RichResponse or SystemIntent in the platform response for agentId: ~~ and intentId: ~~. WebhookStatus: code: 2 message: "Webhook call failed. Error: UNKNOWN." ..
I'm not really well versed in DialogFlow, so I'm not sure what's happening. If anyone has any advice, I'd really appreciate it!
Edit: So, here's what happens that triggers the error. I follow the tutorial all the way to the end. I run the test and type in their test request 'rahman'. The response I get back from the test is the above error. I'm not sure what other details I can add, but if there's anything else I can provide, please let me know!
Edit 2: Following the next comment I received, I opened the cloud functions up in the GCP console and found that a new function was made called dialogflowFirebaseFulfillment. I checked the logs for the 'youtube' function I made, and found this notification:
{
insertId: "..."
labels: {
execution_id: ""
}
logName: "projects/<name of project>/logs/cloudfunctions.googleapis.com%2Fcloud-functions"
receiveTimestamp: "<time>"
resource: {
labels: {…}
type: "cloud_function"
}
severity: "ERROR"
textPayload: "Warning, estimating Firebase Config based on GCLOUD_PROJECT. Intializing firebase-admin may fail"
timestamp: "<time>"
}
I then checked out the new function that was made without me knowing and saw it didn't deploy, having an error: "Function failed on loading user code. Error message: Node.js module defined by file index.js is expected to export function named dialogflowFirebaseFulfillment". I checked the logs and found this:
{
insertId: "<id>"
logName: "projects/<project name>/logs/cloudaudit.googleapis.com%2Factivity"
operation: {
id: "operations/<id>"
last: true
producer: "cloudfunctions.googleapis.com"
}
protoPayload: {
#type: "type.googleapis.com/google.cloud.audit.AuditLog"
authenticationInfo: {
principalEmail: "<email>"
}
methodName: "google.cloud.functions.v1.CloudFunctionsService.UpdateFunction"
requestMetadata: {
destinationAttributes: {
}
requestAttributes: {
}
}
resourceName: "projects/<project name>/locations/us-central1/functions/dialogflowFirebaseFulfillment"
serviceName: "cloudfunctions.googleapis.com"
status: {
code: 3
message: "INVALID_ARGUMENT"
}
}
receiveTimestamp: "<time>"
resource: {
labels: {…}
type: "cloud_function"
}
severity: "ERROR"
timestamp: "<time>"
I know this isn't a good sign, but I also don't know how to really interpret where I should go fix the error. Any ideas would be appreciated, thanks!