java如何登录到Tomcat？

Question

我用Ubuntu 16.04在VPS上安装了Tomcat，一切正常，但我无法登录。目前在文件tomcat-users.xml中有以下设置：

<tomcat-users xmlns="http://tomcat.apache.org/xml"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://tomcat.apache.org/xml tomcat-users.xsd" version="1.0">

<role rolename="tomcat"/>
  <role rolename="role1"/>
  <role rolename="manager-gui"/>
  <user username="tomcat" password="tomcat" roles="tomcat"/>
  <user username="both" password="tomcat" roles="tomcat,role1"/>
  <user username="role1" password="tomcat" roles="role1"/>
  <user username="manager" password="manager" roles="manager-gui"/>
 </tomcat-users>

我使用manager，但我不能进入。告诉我有什么问题？在文件管理器和主机管理器中，所有配置都已配置，否则将出现另一个错误。tomcat用户的位置：/opt/tomcat/conf/tomcat-users.xml

tomcat的内容。服务：

[Unit]
Description=Apache Tomcat Web Application Container
After=network.target

[Service]
Type=forking

Environment=JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-amd64/jre
Environment=CATALINA_PID=/opt/tomcat/temp/tomcat.pid
Environment=CATALINA_HOME=/opt/tomcat
Environment=CATALINA_BASE=/opt/tomcat
Environment='CATALINA_OPTS=-Xms512M -Xmx1024M -server -XX:+UseParallelGC'
Environment='JAVA_OPTS=-Djava.awt.headless=true -Djava.security.egd=file:/dev/./urandom'

ExecStart=/opt/tomcat/bin/startup.sh
ExecStop=/opt/tomcat/bin/shutdown.sh

User=tomcat
Group=tomcat
UMask=0007
RestartSec=10
Restart=always

[Install]
WantedBy=multi-user.target