Internet access problem when changing connection mode (ethernet/wifi) on the same computer

Hello everyone,

I use Fortinet 200D model, and I would like to know something about Fortigate.

I used to connect with ethernet mode and I could access to Internet. But when I change the connection mode (on the same session) and switch from Ethernet to Wifi, ip address changed, and the fortinet doesn't accept this one. After that, internet has been blocked by the fortinet and I couldn't get a access to internet. So, if I turn off the current session, and open it with a wifi connection, that's work. Why ?

Thank you in advance

Have a good day