API Authenticate with two factor authentication enabled fails

[MichaelSFF]

Hi, I have been using the this Quickbase PHP SDK without issue for several years. We recently decided to enable two-factor authentication on our Quickbase realm and were told that we would need to utilize user tokens to authenticate the API. We are now using user tokens with the latest version of the SDK, but it doesn't seem to work. For example, are PHP call to authenticate is the following:

$qb = new Quickbase($username, $password, $userToken, true, null, $appToken, $realm, $hours);

The response is an error code 22 "Sign-in required" with error detail "The page you have requested can be viewed only by users
who have signed in. Please sign in to proceed."
Am doing something wrong, or this in fact an issue with the SDK?
Thank you.