Code verifier and code challenge in Login URL

I am looking to create a simple login page for a custom Window’s desktop application that I am building. What I am trying to accomplish is upon launch of the application’s executable, a login dialogue is created using Qt’s qWebEngine that should connect to the login page of my tenant, and upon successful login using auth0, the dialogue should close and the applications execution process continues.

If I use the following login url: “” the login dialouge successfully connects to my tenants login page. However, when I go to add the code challenge to my login url, I get a local host refused to connect error.

to get the code challenge and code verifier, I am first generating a random string of length 64, then I use randomString.toBase64(QByteArray::Base64UrlEncoding) to generate the code verifier. Using the generated verifier, I then generate the code challenge by hashing the code verifier QCryptographicHash::hash(codeVerifier, QCryptographicHash::Sha256) and then base64 encoding the resulting hashed code, using the same method as above. The code_Challenge is returned as a qString and used in the login URL. However, when included in the login url, the tenants login page is never reached.

Does anyone have any ideas as to why this may be the case?