Jenkins server is not accessible by host name (ip address)

At my macOS 11.4 Big Sur installation the plist file was found here:

/opt/homebrew/Cellar/jenkins-lts/2.xxx.x/homebrew.mxcl.jenkins-lts.plist

Changing ip address to 0.0.0.0 worked as described.

The correct location of the file to edit is /usr/local/opt/jenkins/homebrew.mxcl.jenkins.plist

Found the answer here

It turned out that launch agent was configured to listen only 127.0.0.1 (or localhost). To fixed that edit jenkins agent's plist:

nano /Users/admin/Library/LaunchAgents/homebrew.mxcl.jenkins.plist

and modify httpListenAddress to 0.0.0.0 instead of 127.0.0.1

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs$
<plist version="1.0">
  <dict>
    <key>Label</key>
    <string>homebrew.mxcl.jenkins</string>
    <key>ProgramArguments</key>
    <array>
      <string>/usr/bin/java</string>
      <string>-Dmail.smtp.starttls.enable=true</string>
      <string>-jar</string>
      <string>/usr/local/opt/jenkins/libexec/jenkins.war</string>
      <string>--httpListenAddress=0.0.0.0</string>
      <string>--httpPort=8080</string>
    </array>
    <key>RunAtLoad</key>
    <true/>
  </dict>
</plist>