Can't use authorization code flow in heroku deployed app

[joeriBouwman25]

Hi, when i run my code locally everything works fine, the login with Spotify is successful, and then I got successfully redirected to the next page of my app. However when i run the code in a deployed Heroku app things will go wrong, some users can login without experiencing error and the other half of the users will get an heroku error message (h12= request timeout). Can anyone tell me if there something wrong with the authorization flow or if this error an issue within the heroku app is? (this codet is for an school project)

https://github.com/Juliusmeeuwisse/blok-tech-crocmeisters/tree/dev

[omonkulov]

@joeriBouwman25 I don't know if this is the library or the Spotify API but it also happened to me. Currently, I am trying to understand what happens when an unlisted account tries to use my app. Because in my experience when I tried my app with my friend's account, nothing worked but with my own account everything seemed to work.