Authorization error while opening Tomcat Manager application

I have Tomcat 7.0.55 installed on my BO Server.Now today I had a requirement to deploy a WAR file.To accomplish that I had to login to the Tocat Manager application using below URL http://<hostname>:port/manager/html

But It was giving me authorization error

In order to fix the this access issue, we need to make some changes in tomcat-users.xml file.The process goes as follows:

1. Navigate to the conf folder which is located in G:\SAP BusinessObjects\tomcat\conf
2. Make sure we make a backup of the tomcat-users.xml file. 
3. Open the tomcat-users.xml file in a WordPad/notepad editor. 
4. Once we open the file it should look like:

            <?xml version='1.0' encoding='utf-8'?>

          <tomcat-users>

          <role rolename="tomcat"/>

          <role rolename="role1"/>

          <user username="tomcat" password="tomcat" roles="tomcat"/>

          <user username="role1" password="tomcat" roles="role1"/>

          <user username="both" password="tomcat" roles="tomcat,role1"/>

          </tomcat-users>

• Note that for Tomcat 7 onwards, the roles required to use the manager application were changed from the single manager role to the following four roles. You will need to assign the role(s) required for the functionality you wish to access.

               manager-gui - allows access to the HTML GUI and the status pages
               manager-script - allows access to the text interface and the status pages
               manager-jmx - allows access to the JMX proxy and the status pages
               manager-status - allows access to the status pages only

    5.   We have to add the following two roles:

          <role rolename="manager"/>
          <role rolename="admin"/>

          <role rolename="manager-gui"/>

          <role rolename="manager-script"/>

          <role rolename="manager-jmx"/>

          <role rolename="manager-status"/>

    6.  Once we add the roles, we have to add the following string:

          <user username="administrator" password="password" roles="admin,manager,tomcat,manager-gui,manager-script,manager-jmx,manager-status"/>

    7.  After editing the tomcat-users.xml file, it should look like this:

          <?xml version='1.0' encoding='utf-8'?>

          <tomcat-users>

          <role rolename="tomcat"/>

          <role rolename="role1"/>

          <role rolename="manager"/>

          <role rolename="manager-gui"/>

          <role rolename="manager-script"/>

          <role rolename="manager-jmx"/>

          <role rolename="manager-status"/>

          <role rolename="admin"/>

          <user username="administrator" password="password" roles="admin,manager,tomcat,manager-gui,manager-script,manager-jmx,manager-status"/>

          <user username="tomcat" password="tomcat" roles="tomcat"/>

          <user username="both" password="tomcat" roles="tomcat,role1"/>

          <user username="role1" password="tomcat" roles="role1"/>

          </tomcat-users>

8. Go to Central Configuration Manager and restart the Tomcat Server. 
9. Open Internet Explorer and type http://hostname:port. In my case the port was 8080 
10. It will prompt you for username and password
11. Enter the credentials as specified in the tomcat-users.xml file.

Reference:-1308046 - How to Deploy WAR files in Business Objects Enterprise XI 3.1 using Tomcat Manager?