prerender.io and asp.net core verification failed

I used aurelia (single page application) to create a website. Since SEO meta tags are added during runtime on client side search engines cant pick up these tags. I found prerender.io as solution for this problem, however I just cant get it to verify my application.

My backend is implemented asp.net core and is running as a app service. I used this Middleware: https://github.com/dingyuliang/prerender-dotnet/wiki/Prerender-Middleware-for-ASP.NET-Core

My configuration is:

{
  "PrerenderConfiguration": {
    "ServiceUrl": "http://service.prerender.io",
    "Token": null,
    "CrawlerUserAgentPattern": null,
    "WhiteListPattern": null,
    "BlackListPattern": "lib|css|js",
    "AdditionalExtensionPattern": null,
    "ProxyUrl": null,
    "ProxyPort": 80
  }
}

I also already tried setting the "Token" in the Configuration to the one I can see on the website after login in the upper left corner. Is there any step I'm missing or are the instructions on the github page incomplete?

Copyright Notice：Content Author:「Valentin Weiß」，Reproduced under the CC 4.0 BY-SA copyright license with a link to the original source and this disclaimer.
Link to original article：https://stackoverflow.com/questions/71294548/prerender-io-and-asp-net-core-verification-failed