Google Cloud Function - SendGrid - 400 Bad Request - node.js

Question

I'm trying to send an email using SendGrid in my Google Cloud Function. I have my key in the Firebase environment variables, so that's present.
const sgMail = require('#sendgrid/mail');
sgMail.setApiKey(SENDGRID_API_KEY);
Here is my GCF .ts code:
Code
const msg = {
to: to,
from: from,
subject: 'Email Subject',
content: [{
type: "text/html",
value: body
}]
};
await sgMail.send(msg)
.then(r => {
console.log(r);
});
When I trigger the function and check my logs, this is the error I get:
Error
error: { Error: Bad Request
at ResponseError (node_modules/#sendgrid/mail/node_modules/#sendgrid/helpers/classes/response-error.js:19:5)
at Request.http [as _callback] (node_modules/#sendgrid/mail/node_modules/#sendgrid/client/src/classes/client.js:124:25)
at Request.self.callback (node_modules/#sendgrid/mail/node_modules/request/request.js:185:22)
at emitTwo (events.js:106:13)
at Request.emit (events.js:191:7)
at Request.<anonymous> (node_modules/#sendgrid/mail/node_modules/request/request.js:1161:10)
at emitOne (events.js:96:13)
at Request.emit (events.js:188:7)
at IncomingMessage.<anonymous> (node_modules/#sendgrid/mail/node_modules/request/request.js:1083:12)
at IncomingMessage.g (events.js:292:16)
code: 400,
message: 'Bad Request',
response:
{ headers:
{ server: 'nginx',
date: 'Sun, 16 Dec 2018 16:27:56 GMT',
'content-type': 'application/json',
'content-length': '402',
connection: 'close',
'access-control-allow-origin': 'https://sendgrid.api-docs.io',
'access-control-allow-methods': 'POST',
'access-control-allow-headers': 'Authorization, Content-Type, On-behalf-of, x-sg-elas-acl',
'access-control-max-age': '600',
'x-no-cors-reason': 'https://sendgrid.com/docs/Classroom/Basics/API/cors.html' },
body: { errors: [Object] } } }
Does anyone have any familiarity with this error? It mentions CORS, but that makes no sense, because it's a cloud function, not browser. The SendGrid API isn't that great, it mostly goes over the field names and provides no examples. Thanks for any help provided!
EDIT
Just to update the question, in the front end response I send myself I found a different error than the console.log(error) in the GCF logs:
"Email failed: Bad Request (400)
The from object must be provided for every email send.
It is an object that requires the email parameter,
but may also contain a name
parameter. e.g. {"email" : "example#example.com"} or
{"email" : "example#example.com", "name" : "Example Recipient"}.
from.email
http://sendgrid.com/docs/API_Reference/Web_API_v3/Mail/errors.html#message.from"
EDIT 2: SOLUTION
My from email source comes from a document in Firestore, and I was trying to get a field that didn't exist because I was querying the wrong document, therefore from was undefined. Corrected it, as well as removed "content" in the msg object per the suggestion / answer below, and everything works fine.

Answer 1

According to the documentation ...the msg has the wrong elements:
const sg = require('#sendgrid/mail');
sg.setApiKey(process.env.SENDGRID_API_KEY);
const msg = {
to: 'test#example.com',
from: 'test#example.com',
subject: 'Sending with SendGrid is Fun',
text: 'and easy to do anywhere, even with Node.js',
html: '<strong>and easy to do anywhere, even with Node.js</strong>',
};
sg.send(msg).then(() => {
/* assume success */
})
.catch(error => {
/* log friendly error */
console.error(error.toString());
/* extract error message */
const {message, code, response} = error;
/* extract response message */
const {headers, body} = response;
});