macbook air stopped connecting to internet? other computers have no problem connecting
macbook air will not connect to internet anymore? no problem with other computers
Hi there, try and use the built in wifi diagnostic tools
Use the built-in diagnostic tools
Wi-Fi Recommendations. Click Wi-Fi 
in Control Center or the menu bar and check for a menu item named Wi-Fi Recommendations. If you see it, your Mac has detected an issue and has recommendations. Choose Wi-Fi Recommendations to learn more.*
Wireless Diagnostics. Press and hold the Option key on your keyboard while clicking Wi-Fi in Control Center or the menu bar, then choose Open Wireless Diagnostics from the menu. Learn more about using Wireless Diagnostics to analyze your wireless environment.
Also, check in the control center if wifi is greyed out. If it is greyed out, it is most likely a hardware problem with your built in wifi antenna. Contact - Official Apple Support to set up service for your device if this is the cas e