login request got timeout 408

Hi, I am new to gatling. I can login my test system on browser, but when I use gatling to send the login request, got 408. My test system is a tomcat application,
anyone know why I got 408? Thanks in advance for your help.

HTTP 408 simply means the request timed out.


The server did not receive a complete request message within the time that it was prepared to wait.