Whilst trying to look at some API calls via the Swagger UI at TfL Unified API, I found that none of the endpoint tests worked. It looks like the UI has been generated to call https://api.digital.tfl.gov.uk/ which isn’t accessible to me.
Are you starting with APIs: List - Transport for London - API ?
We have issues with the swagger generator for the API and we’ll be deprecating this soon.
We’re looking into a replacement swagger generator that is complete and has the correct URLs.