I set up raspberry pi 4 with this tutorial : Access point as WiFi router/repeater, optional with bridge.
How do I turn off ap mode and how to enable it again?
When I plugged in ethernet port, the pi still broadcast wifi but there is no internet connection. (School ethernet port)
Also how to connect to wpa2 enterprise network with certificate?
This is an Answer to part of the Question "but the wifi bar is not working" which has since been deleted.
Because it uses systemd-networkd the new all-singing all-dancing network manager - which unfortunately is mind boggling difficult to use.
Raspbian uses dhcpcd and the network icon is a GUI front end to this, so it won't work if you disable dhcpcd.
Also how to connect to wpa2 enterprise network with certificate?
You should be able to do this by manually editing /etc/wpa_supplicant/wpa_supplicant.conf (or the particular wpa_supplicant you are using). There are examples of how to configure wpa_supplicant for enterprise networks on this site and these should work in the same way.
If I understand your question right you just want do stop the Access Point. This can simply be done with:
rpi ~$ sudo systemctl stop wpa_supplicant@wlan0.service
To start it again just do:
rpi ~$ sudo systemctl start wpa_supplicant@wlan0.service
This will only stop/start temporary. On boot up the AP will always start. To avoid this you have to disable the service. Then you have to enable it again.
rpi ~$ sudo systemctl disable wpa_supplicant@wlan0.service
rpi ~$ sudo systemctl enable wpa_supplicant@wlan0.service
This takes effect only after reboot. To disable/enable the service and stop/start it now you can execute:
rpi ~$ sudo systemctl disable --now wpa_supplicant@wlan0.service
rpi ~$ sudo systemctl enable --now wpa_supplicant@wlan0.service
