Swagger ui throwing an exception for Hashtable when i use Newtonsoft.Json version 12.0.1
Newtonsoft is not one of our projects and we don't know it well enough to provide support for it. The error you're getting is from it and not from Swagger UI. Looking at the stack trace you provided, it looks like it may originate from Swashbuckle, which is again not one of our projects, but it does wrap Swagger UI in it. Your best bet is to file an issue either with Newtonsoft or Swashbuckle and hopefully one of them can help you out.