Google Spreadsheet Api not working on mobile devices - database

Question

I'm using Google Spreadsheets as a lightweight database for my React App. The app is a wedding website and the idea is for users to be able to RSVP and the response gets saved in a Google Spreadsheet. See GitHub for a visual representation of what I mean: https://github.com/michelleroos/mimirgettingmarried
It's working as intended on desktop, meaning RSVP responses get saved to the sheet, but not on mobile and I can't figure out why.
Would love your input! If I could even just understand where to start looking that would be great but there is not a lot of information out there on Google Spreadsheet Api.
const express = require("express");
const app = express();
const { google } = require('googleapis');
const PORT = process.env.PORT || 3001; // use live port or the declared one
var cors = require('cors');
app.use(cors())
const bodyParser = require('body-parser');
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));
const auth = new google.auth.GoogleAuth({
keyFile: "./config/credentials.json",
scopes: 'https://www.googleapis.com/auth/spreadsheets',
});
const spreadsheetId = "1-R0vjBCOD5hcipk9AQbVUwQAH_0dFvQB2qs5gxsxWg0";
const range = "rsvp";
// api endpoint returns a CB. We decide what to do w res thru CB
app.get("/api/rsvp", async (req, res) => {
// create client instance for auth
const client = await auth.getClient();
// create Google sheets API instance
const googleSheets = google.sheets({ version: "v4", auth: client })
// read rows
const getRows = await googleSheets.spreadsheets.values.get({
auth,
spreadsheetId,
range,
});
// express/app sends to the client (the body)
res.send(getRows.data.values);
});
app.post("/api/rsvp", async (req, res) => {
// create client instance for auth
const client = await auth.getClient();
// create Google sheets API instance
const googleSheets = google.sheets({ version: "v4", auth: client })
const writeRows = await googleSheets.spreadsheets.values.append({
auth,
spreadsheetId,
range,
valueInputOption: "USER_ENTERED", // parses info
resource: {
values: [
// Object.keys(req.body), // header
Object.values(req.body) // values
]
}
})
res.send(writeRows);
});
app.listen(PORT, () => {
console.log(`Server listening on ${PORT}`);
});