Hello I am currently getting the error:
I am using zoomappsdk for client side
{“reason”:“Invalid authorization code [REDACTED]”,“error”:“invalid_grant”}
I used the zoomapp sdk and used the authorize and onauthorized functions on the client side to get the authorization code
{code: “###”, result: true, timestamp: ###, redirectUri: "https://###.ngrok.io/”}
Then I send the code to the backend with a code_verifier to then the server sends a post to
“https://zoom.us/oauth/token” with the parameters
?grant_type=authorization_code&code=###&code_verifier=###&redirect_uri=###
No Luck 
Can someone please help with this Ive been stuck on why its giving authorization code error the last two days
Heres what I am doing to run the current code challenge
async function generateCodeChallenge() {
// Generate a random string for the challenge
const challenge = await generateRandomString(64);
// Convert the challenge to a buffer
const challengeBuffer = new TextEncoder().encode(challenge);
// Encode the buffer using plain encoding
const codeChallenge = btoa(String.fromCharCode(…new Uint8Array(challengeBuffer)));
// Generate a random string for the verifier
const verifier = await generateRandomString(64);
// Convert the verifier to a buffer
const verifierBuffer = new TextEncoder().encode(verifier);
// Encode the buffer using base64
const codeVerifier = btoa(String.fromCharCode(…new Uint8Array(verifierBuffer)));
return { codeChallenge, codeVerifier };
}
On the backend here is what I am running for calling zoom server
const zoomtokenep = “https://zoom.us/oauth/token”;
sanitize(req)
const myappredirect = req.query.redirectUri;
console.log(“zoomcallback”)
if (req.query.code) {
console.log(“CODE VERIFIER”)
console.log(req.query.code_verifier)
console.log(req.query.code)
const zoomclientid = “Z***”
const zoomclientsec = “T***”
const auth = ‘Basic ’ + Buffer.from(zoomclientid + ‘:’ + zoomclientsec).toString(‘base64’);
console.log(auth)
var url = zoomtokenep + ‘?grant_type=authorization_code&code=’ +
req.query.code + ‘&code_verifier=’+req.query.code_verifier +’&redirect_uri=’ + myappredirect;
request.post({
url: url,
headers: {
“Content-Type”:“application/x-www-form-urlencoded”,
“Authorization”: auth
}
}, function(error, response, body) {
console.log(response)
if (error) {
console.log("Error when getting Zoom token = " + error);
return;
}
body = JSON.parse(body);
if (body.access_token) {
accessToken = body.access_token;
// Process and securely store these tokens
res.send({ output: accessToken});
} else {
console.log(“FATAL - could not get zoom token”);
}
return;
});
} else {
console.log(“Missing code from Zoom”);
}
});