I'm having a problem with the game...

[Dizzard]

For some reason it seems like I'm only able to connect/load up the game when I'm connected to WiFi. So far the only two times recently that I've been able to get past the login screen is either when I'm at home or using the WiFi on a bus.

If I'm just wandering around I'm never able to log in with just my mobile data connection. It just hangs after I try to log in with my google account.

Is there something I'm doing wrong? (or not doing)

 

[Zexy]

I've got a similar problem sometimes as well. Most of the time the servers were supposedly down so I didn't pay much attention to it but I eventually got the problem where the game does load but the map doesn't because "GPS signal can't be found" even if you have GPS on and are outdoors. After some search I figured out what the problem really is:

For some reason, the game works more properly when you have Wi-Fi on. Even if you just have it on but use a mobile data connection instead. Guess it was some kind of overlook on the programmers' part, perhaps having it on sets some important flag on, but when it is on the game's seemingly working better even if you don't really use Wi-Fi to connect.

Hopefully this will fix your issue; it isn't definitely the solution (might be a problem from your device's end or the servers acting up again) but it's helped several times.

edit: 2 more tricks I use that I just remembered:
1) Go to Settings, Applications and forcibly close Pokemon Go from there then try to use the app again.
2) If nothing else works, try restarting your entire device. It's done the trick a few times.