smartphone doesn't recognize internet connection for 1 app

I went to a new Lidl store Thursday and found out I had to have the app in order to get their discounts. For some reason, the MyLidl app doesn't work on my smartphone and even after I had to get on my PC and Joined, that app still does not recognize me as having the internet on my smartphone even though I have no problem getting on the Internet otherwise. I have called Lidl, Verizon, Spectrum, Samsung and Best Buy and went to Best Buy and nobody can figure it out. And I probably spent at least 45 minutes on each of those phone calls, not counting trying to figure it out myself. I can get in that MyLidl app on my tablet with no problem. So, Bitdefender is my last hope for figuring out why that MyLidl app does not recognize an internet connection on my smartphone. For some reason, I couldn't connect to set up the app using data in their store so I ended up using the unsecured Wi-Fi in the store but I turned on the Bitdefender VPN so even though the VPN is turned off now, I still can't get in the MyLidl app that's on my smartphone. Are there any settings I have on your Bitdefender app that could be preventing the MyLidl app from recognizing an internet connection on my smart phone? Any help would be greatly appreciated. Thank you very much.