I installed the tomcat 8.5.35 remotely on other machine. I did the following steps to solve this problem:
1. Change $TOMCAT_HOME/conf/server.xml (Same as the course)
<role rolename=”manager-script”/>
<role rolename=”manager-gui”/>
<role rolename=”admin-gui”/>
<user username=”tomcat” password=”tomcat” roles=”manager-script,admin-gui,manager-gui”/>
2. Because the default version come with Catalina directory, I put another file in the $TOMCAT_HOME/conf/Catalina/localhostfolder, named manager.xml, in which the content is:
<?xml version=”1.0″ encoding=”UTF-8″?>
<Context privileged=”true” antiResourceLocking=”false”
docBase=”${catalina.home}/webapps/manager”>
<Valve className=”org.apache.catalina.valves.RemoteAddrValve” allow=”^.*$” />
</Context>
3. Save and restart and profit.