Postman not recognizing response

Hello. Iโ€™m new to Postman and am having trouble establishing a simple request-response relationship with a simple HTTP/1.1 server.
I am sending a GET request to my server and Postman is indicating a timeout without response. I know Postman should be receiving the following string: โ€œHTTP/1.1 400 Bad Request\r\nโ€

If I telnet into my server and send any arbitrary command I get the above string as intended. I can see in my server code that Postman is making a connection and sending a request. I can also see that my server is responding with the Bad Request string. But Postman doesnโ€™t recognize the response.

Any ideas?