Selenium Grid_Firefox instance not running the test
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I am facing an issue with Grid using Webdriver. 
Whenever I launch the test with two nodes (one for Chorme , other for Firefox) , the chrome instance opens and test runs fine. 
Whereas in case of firefox only blank browser window opens up but the test does not run on this.

Following are the commands I am using :

To start the Grid Hub 

"java -jar selenium-server-standalone-2.21.0.jar -role hub"

To start the remote control supporting Google Chrome 

"Java -Dwebdriver.chrome.driver=D:\Selenium\softwares\chromedriver_win_20.0.1133.0\chromedriver.exe -jar selenium-server-standalone-2.21.0.jar -role webdriver –hubhttp://localhost:4444/grid/register -browser browserName=chrome,platform=WINDOWS -port 5556"

To start another remote control supporting Firefox 

"Java -jar selenium-server-standalone-2.21.0.jar -role webdriver –hubhttp://localhost:4444/grid/register -browser browserName=firefox,platform=WINDOWS -port 5555"

Thanks in Advance!
