App connection trouble

Hello everybody.
I was confronted to a weird situation: I launched my app on my device from Tizen Studio (my app requires an internet connection) and it worked fine.
Then, I left my house with my device and I came back home after a few hours. When I arrived my device connected to the Wifi Network but my app couldn't work until I connected the device to tizen studio and I relaunched the app from it. 
Please, can someone explain me why I had to relaunch the app from tizen studio to make it works whereas the app was already installed on the device and the device was connected to the Wifi Network ? Thank you for your help.