Thank you for your reply.
I am using KepServerEx in ThingWorx, not using Connection Server.
At the login page (http://localhost:8080/Thingworx/FormLogin/<<Company>>), i key in the correct username and password and able to login. But Thingworx redirect me to a blank page (http://localhost:8080/Thingworx/action-login) if i key in wrong username and password.
I had found a related post and done the test but not working.
i) I had opened new tab with URL Thingworx/Composer/index.html and able to login without key in username and password in private window
ii) My ThingWorx version is 7.2.0-b155, had set the Home Mashup (and Mobile Mashup) to my home mashup at the Organization level
iii) I had removed "Users" group from "Everyone" organization and added the user groups i defined, of course i had set the user under the member of the group
I also noticed that after i login successfully, ThingWorx will redirect me to http://localhost:8080/Thingworx/Runtime/index.html#mashup=Home and then switch to http://localhost:8080/Thingworx/Runtime/index.html#master=MasterMashup&mashup=Home immediately and last there, is it correct?
Please advise. Thank you
Redirects to a blank page usually occurs when you have a proxy server (that has not been configured to redirect correctly) or when using an older version of the Connection Server. The Master redirect is fine since you have a Master setup for your Home Mashup. Can you open up your browser tools (with the F12 key) and see the requests (and responses) made on the Network tab (before logging in the FormLogin page)?