I can't exactly replicate but I did get it to work once but if I open a new project and change base-url to for instance localhost:54304 I can see the request is being sent to localhost:5000/api/blah when I plug in {{base-url}}/api/blah to a new step. I even had it where I got it to recognise the right port but then realised I had made a typo "localhost:5430" and couldn't get it to recognise the new value