Choose the Apple menu 
> System Preferences on your Mac, then click Network
. Select the network connection you want to check in the list at the left.
A status indicator next to the connection shows its status:
- Green means the service is active (turned on) and connected.
- Yellow means it’s active but not connected.
- Red means the service has not been set up.
Please see the Apple support links below for more help troubleshooting Mac-related issues.
Troubleshoot joining a Wi-Fi network on Mac
Troubleshoot an Ethernet device on Mac
Troubleshoot connecting your Mac to the internet