I recently switched to a Pixel 2 XL and have been unable to connect through data since. The game works fine on wifi and will even stop working when switched to data.
I have tried numerous fixes online such as making sure background data is allowed for the app, Google services, and the Google play store. I tweaked my Google account security settings, cleared out all my settings, and even removed all my Google account data and re-added it through the app.
I've reached the point of frustration, and I'm out of solutions. If anyone can help me with this issue it would be much appreciated. I'm unsure if it's a Pixel issue, Android Oreo issue, or a Pokemon Go issue. Any and all help is appreciated.