NullPointerException - HTML not loaded proper

Gatling (Open-Source)
1 
**Getting this error as there is no gif present for spacer.gif** 

Scala class for testing - 

package computerdatabase

import scala.concurrent.duration._

import io.gatling.core.Predef._
import io.gatling.http.Predef._
import io.gatling.jdbc.Predef._

class PracticeSimulation extends Simulation {

  val httpProtocol = http
    .baseUrl("[http://newtours.demoaut.com](http://newtours.demoaut.com)")
    .inferHtmlResources()
    .userAgentHeader("Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.130 Safari/537.36")

  val headers_0 = Map(
    "Accept" -> "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9",
    "Accept-Encoding" -> "gzip, deflate",
    "Accept-Language" -> "en-GB,en-US;q=0.9,en;q=0.8",
    "Origin" -> "[http://newtours.demoaut.com](http://newtours.demoaut.com)",
    "Upgrade-Insecure-Requests" -> "1")

  val headers_5 = Map(
    "Accept" -> "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9",
    "Accept-Encoding" -> "gzip, deflate",
    "Accept-Language" -> "en-GB,en-US;q=0.9,en;q=0.8",
    "Upgrade-Insecure-Requests" -> "1")

  val headers_6 = Map(
    "Accept" -> "image/webp,image/apng,image/*,*/*;q=0.8",
    "Accept-Encoding" -> "gzip, deflate",
    "Accept-Language" -> "en-GB,en-US;q=0.9,en;q=0.8")

  val scn = scenario("RecordedSimulation")
    .exec(http("request_0")
      .post("/login.php")
      .headers(headers_0)
      .formParam("action", "process")
      .formParam("userName", "mercury")
      .formParam("password", "mercury")
      .formParam("login.x", "18")
      .formParam("login.y", "15")
2

Error message is pretty explicit: can’t investigate without knowing the HTML payload.