400 Invalid authorization code

I have an authorization website that I created on “wix.com” with that velo stuff and javascript. The first time the user logged in it shows “400 Invalid authorization code” on the “post” request:

https://id.twitch.tv/oauth2/token?client_id=client_id&client_secret=client_secret&code=code&grant_type=authorization_code&redirect_uri=website

The next time the user goes on that website there is no error. The website:

https://id.twitch.tv/oauth2/authorize?response_type=code&client_id=client_id&redirect_uri=website&scope=moderator:read:chatters+moderator:read:followers+channel:read:subscriptions

I read that it can be a double usage of the code by twitch given. I didn’t find how to see the exact made http requests on “wix.com

I also found out, that this error just occurs, if the user visits the website the first time like it has something to do with cookies or something like that.