Symptoms
Only blank screen is observed while launching webtool.
Verified that customer is using supported server and web Browser to launch webtools.
Verified that there is No security pop up blocked.
Cause
Starting with Brocade FOS 9.0 Web Tools US English is the only language supported. Hence setting to other language in internet browser may result in Web Tools showing as blank page.
Resolution
Change the browser language setting to US English and try to launch webtools.