Apache Tomcat cannot run on port 80 on Windows 10

I try to publish java web application on port 80 via Apache Tomcat 7.0. Server computer that has the Tomcat uses Windows 10.

• I setup the web app into C:\Program Files\Apache Software Foundation\Tomcat 7.0\webapps.
• After port forwarding on the modem that the server is connected to, I can connect my web app with the url - http://[PublicIpAddress]:8080/AppName
• However, I WANT TO CONNECT MY WEB APP ON PORT 80, that's why I make port-forwarding for port 80 as I did before for port 8080.

• Then, I configure server.xml file of apache tomcat like;

  <Connector port="80" protocol="HTTP/1.1"
         connectionTimeout="20000"
         redirectPort="8443" />
  
  

• But, at this time, when i enter http://[PublicIpAddress]/AppName or http://[PublicIpAddress]:80/AppName into url bar of Firefox or Chrome, browser cannot be connected to the server and open my web app.

• When, I look up for an app that use port 80(I think that port-80 is already used by another app!), I see this on command prompt;

• When I look up for PID - 9324 from task manager, I see that it is used for Tomcat7.exe. It means that there is no app using port-80!

• In addition, when I use Wireshark to check packages sent and received in server-side; (188.57... client public ip addr.; 192.168.1.132 server-side local ip address)

Based on this picture, I see that the modem can make port-forwarding properly, but I don't know why, there is something happened in server-side and the web app cannot be showed on client.

How can I publish this web app on port 80 via Apache Tomcat 7.0?