Cannot log in Tomcat

Operating System: OS X, Tomcat version: 8.0.23 Browser:Chrome;

I have setting the user in the file"tomcat-users.xml" as directed and restart Tomcat, but I still cannot log in. Why? And how can I slove this problem?

here is my configuration in "tomcat-users.xml"

And once after I enter the user name and password and click "log in" ,this window show out again

If I click "cancel", the page shows this :