I have read a lot of topics in stackoverflow for solve my problem, but none was useful.
When I tried to log in Manager App ([http://localhost:8080/manager/html][1]) usin
Solutions above probably solved your problem.The locked user solution tipped me off on my issue.
Something weird I noticed... Don't know how it happened.
After installing a new tomcat7 I ended up with a "tomcat-users.xml" file owned by user root and group root.
I found out because catalina.out contains a few lines like "javax.naming.NamingException: /var/lib/tomcat7/conf/tomcat-users.xml (Permission denied)"
After changing file ownership to user "root" & group "tomcat7" fixed my login issue.