|tear down| keyword is sending an exception in FitnesseForAppian-18.2.1

After my test, the browser closes successfully but the keyword is sending an exception that prevents the test to be passed. Please refer to the exception message below, thanks!

__EXCEPTION__:org.openqa.selenium.WebDriverException: quit
Build info: version: '3.4.0', revision: 'unknown', time: 'unknown'
System info: host: 'W7PHSSPNJSL6QN2', ip: '10.51.165.197', os.name: 'Windows 7', os.arch: 'amd64', os.version: '6.1', java.version: '1.8.0_181'
Driver info: org.openqa.selenium.firefox.FirefoxDriver
Capabilities [{moz:profile=C:\Users\rcarrao\AppData\Local\Temp\rust_mozprofile.WG1Liw951iZM, rotatable=false, timeouts={implicit=0.0, page load=300000.0, script=30000.0}, pageLoadStrategy=normal, platform=ANY, specificationLevel=0.0, moz:accessibilityChecks=false, acceptInsecureCerts=false, browserVersion=52.4.0, platformVersion=6.1, moz:processID=16608.0, browserName=firefox, javascriptEnabled=true, platformName=windows_nt}]
Session ID: 1a672811-edf7-4e4b-ad07-a6309c9c6e40
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) [rt.jar:1.8.0_181]
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source) [rt.jar:1.8.0_181]
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) [rt.jar:1.8.0_181]
	at java.lang.reflect.Constructor.newInstance(Unknown Source) [rt.jar:1.8.0_181]
	at org.openqa.selenium.remote.http.W3CHttpResponseCodec.createException(W3CHttpResponseCodec.java:150) [selenium-remote-driver-3.4.0.jar]
	at org.openqa.selenium.remote.http.W3CHttpResponseCodec.decode(W3CHttpResponseCodec.java:115) [selenium-remote-driver-3.4.0.jar]
	at org.openqa.selenium.remote.http.W3CHttpResponseCodec.decode(W3CHttpResponseCodec.java:45) [selenium-remote-driver-3.4.0.jar]
	at org.openqa.selenium.remote.HttpCommandExecutor.execute(HttpCommandExecutor.java:164) [selenium-remote-driver-3.4.0.jar]
	at org.openqa.selenium.remote.service.DriverCommandExecutor.execute(DriverCommandExecutor.java:82) [selenium-remote-driver-3.4.0.jar]
	at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:637) [selenium-remote-driver-3.4.0.jar]
	at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:694) [selenium-remote-driver-3.4.0.jar]
	at org.openqa.selenium.remote.RemoteWebDriver.quit(RemoteWebDriver.java:533) [selenium-remote-driver-3.4.0.jar]
	at com.appiancorp.ps.automatedtest.fixture.BaseFixture.tearDown(BaseFixture.java:870) [fitnesse-for-appian-18.2.1.jar]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [rt.jar:1.8.0_181]
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) [rt.jar:1.8.0_181]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) [rt.jar:1.8.0_181]
	at java.lang.reflect.Method.invoke(Unknown Source) [rt.jar:1.8.0_181]
	at fitnesse.slim.fixtureInteraction.DefaultInteraction.methodInvoke(DefaultInteraction.java:81) [fitnesse-20160515-standalone.jar]
	at fitnesse.slim.MethodExecutor.callMethod(MethodExecutor.java:57) [fitnesse-20160515-standalone.jar]
	at fitnesse.slim.MethodExecutor.invokeMethod(MethodExecutor.java:38) [fitnesse-20160515-standalone.jar]
	at fitnesse.slim.MethodExecutor.findAndInvoke(MethodExecutor.java:72) [fitnesse-20160515-standalone.jar]
	at fitnesse.slim.FixtureMethodExecutor.execute(FixtureMethodExecutor.java:20) [fitnesse-20160515-standalone.jar]
	at fitnesse.slim.StatementExecutor.getMethodExecutionResult(StatementExecutor.java:135) [fitnesse-20160515-standalone.jar]
	at fitnesse.slim.StatementExecutor.call(StatementExecutor.java:108) [fitnesse-20160515-standalone.jar]
	at fitnesse.slim.instructions.CallInstruction.executeInternal(CallInstruction.java:35) [fitnesse-20160515-standalone.jar]
	at fitnesse.slim.instructions.Instruction.execute(Instruction.java:29) [fitnesse-20160515-standalone.jar]
	at fitnesse.slim.ListExecutor$Executive.executeStatement(ListExecutor.java:49) [fitnesse-20160515-standalone.jar]
	at fitnesse.slim.ListExecutor$Executive.executeStatements(ListExecutor.java:43) [fitnesse-20160515-standalone.jar]
	at fitnesse.slim.ListExecutor.execute(ListExecutor.java:85) [fitnesse-20160515-standalone.jar]
	at fitnesse.slim.SlimServer.executeInstructions(SlimServer.java:84) [fitnesse-20160515-standalone.jar]
	at fitnesse.slim.SlimServer.processOneSetOfInstructions(SlimServer.java:77) [fitnesse-20160515-standalone.jar]
	at fitnesse.slim.SlimServer.tryProcessInstructions(SlimServer.java:64) [fitnesse-20160515-standalone.jar]
	at fitnesse.slim.SlimServer.serve(SlimServer.java:49) [fitnesse-20160515-standalone.jar]
	at fitnesse.slim.SlimService.handle(SlimService.java:154) [fitnesse-20160515-standalone.jar]
	at fitnesse.slim.SlimService.acceptOne(SlimService.java:162) [fitnesse-20160515-standalone.jar]
	at fitnesse.slim.SlimService.accept(SlimService.java:124) [fitnesse-20160515-standalone.jar]
	at fitnesse.slim.SlimService.startWithFactory(SlimService.java:76) [fitnesse-20160515-standalone.jar]
	at fitnesse.slim.SlimService.main(SlimService.java:56) [fitnesse-20160515-standalone.jar]