Authorize User endpoint only works on second attempt

For the first step when authenticating a user using OAuth 2.0, my application opens a browser to the following URL: 

https://app.box.com/api/oauth2/authorize?response_type=code&client_id=j0lwz7kt0tvbvbuqmea6ltlfuj787v3w&redirect_uri=https://api.bridgelabs.com/v1/accounts/redirect&state=R4bhoZ4JChGjK8bJxfNvuEPZK5e7Hu3h

On the first attempt, the browser is incorrectly redirected to a page that says: "Oops! We can't seem to find the page you're looking for.". This page has the following URL:

https://app.box.com/login/mfa?redirectUrl=%2Fapi%2Foauth2%2Fauthorize%3Fresponse_type%3Dcode%26client_id%3Dj0lwz7kt0tvbvbuqmea6ltlfuj787v3w%26redirect_uri%3Dhttps%3A%2F%2Fapi.bridgelabs.com%2Fv1%2Faccounts%2Fredirect%26state%3DDJfkFIkuCJb7s5jcZ8TEdnepXG2CNvMM

However, if I then repeat the first step by opening a browser to the original URL, the browser correctly displays the OAuth page that lets the user "Grant access to Box".

I'm not sure how to fix this problem. It used to work, but this problem has only recently been brought to my attention. I suspect this might be a cookie issue on your end because the incorrect behavior doesn't appear to happen unless I'm logged into the Box website.