Environment Variable "API_SECRET" on Vercel Deployment Issue

I'm encountering an issue with environment variables (API_SECRET) when deploying my Node.js application to Vercel. Despite adding the environment variables correctly, the application fails to recognize API_SECRET during deployment.

Folder Structure:

project-root/│├── .env├── firebase.js├── server/│├── controllers/││├── createVirtualAccount.js││├── handlePaymentNotification.js││└── ...│├── routes/││├── routes.js││└── ...│└── index.js└── package.json

Deployment Platform: VercelNode.js Version: 20.14.0Framework/Libraries: Node.js, Express (if applicable)

Code Snippet (createVirtualAccount.js):

import fetch from 'node-fetch';import dotenv from 'dotenv';dotenv.config();const apiKey = process.env.API_KEY;const apiSecret = process.env.API_SECRET;export const createVirtualAccount = async (req, res, next) => {    try {        if (!apiKey || !apiSecret) {            throw new Error('API_KEY or API_SECRET is missing');        }        const { email, name, phoneNumber, bankcode, account_type, businessid, bvn } = req.body;        const options = {            method: "POST",            body: JSON.stringify({                email,                name,                phoneNumber,                bankcode,                account_type,                businessid,                bvn            }),            headers: {'api-key': apiKey,'api-secret': `Bearer ${apiSecret}`,'Content-Type': 'application/json'            }        };        const apiResponse = await fetch('https://api.payvessel.com/api/external/request/customerReservedAccount', options);        if (!apiResponse.ok) {            const errorText = await apiResponse.json();            throw new Error(`Error: ${apiResponse.status} - ${errorText}`);        }        const data = await apiResponse.json();        res.status(201).json(data);    } catch (error) {        next(error);    }};

I have verified that the .env file is correctly formatted and the environment variables are accessed using dotenv.config().Despite adding API_SECRET to both my local .env file and Vercel environment variables, the application fails to recognize API_SECRET during deployment on Vercel.

Desired Outcome:I'm looking for guidance on how to troubleshoot and resolve the issue with API_SECRET not being recognized during deployment on Vercel. Any suggestions or insights into potential causes or debugging steps would be greatly appreciated.