SwaggerUI behind a reverse proxy

Hey everyone,

I once was using swagger ui (swashbuckle with .Net 5.0) behind a reverse proxy and it was magically working. The proxy redirects "/api" to a different hosts base directory "/".

When calling /api/swagger these days I got redirected to "/api/swagger/index.html" but now I get redirected to "/swagger/index.html" where swagger ui isn't listening. Can someone help me to find the old magic? What Http-Headers where maybe set that made swagger ui know that it was used behind a reverse proxy?

BR

Tristan