Here’s my tomcat-users.xml:
<?xml version='1.0' encoding='utf-8'?>
<tomcat-users>
<role rolename="tomcat"/>
<role rolename="role1"/>
<role rolename="admin"/>
<role rolename="manager"/>
<user username="tomcat" password="tomcat" roles="tomcat"/>
<user username="MyAdmin" password="pswd" roles="admin,manager"/>
</tomcat-users>
I restart tomcat and go to localhost:8080/manager. It asks me to log in. I enter the admin/manager credentials (u = MyAdmin and p = pswd) and it fails, giving me the following 403:

Whats going on here? I’m almost 100% sure I have the XML configured right!?! Is it possible something else isn’t configured properly?
I just realized from your screenshot you are using Tomcat 7.
Roles have changed a little bit. See the updated documentation
update your role to the appropriate setting.