This problem just happened this morning, I can log into pokemon go when using mobile data, but it just won't load when I am using the wifi inside the house. Does anyone know how to fix this?
If it works on Mobile data but not Wi-Fi, the problem is in your Wi-Fi.
Several things you may want to check if Wi-Fi isn't working for you:
Check that your Wi-Fi actually has internet (i.e. check that you can view websites and such). It is very likely that you may be connected to Wi-Fi but have no internet connection, such as if your router has an internet connectivity problem.
Extreme case: Check that your internet provider does not block any websites/databases from where information is necessary, such as real-time data for Pokemon and Pokestops.
Extreme case: Check that if you have an app to monitor apps and what types of data connectivity, including mobile data and Wi-Fi, that they can use, Wi-Fi is not blocked for Pokemon Go. In other words, check that Pokemon Go is allowed to use Wi-Fi on your device.
It is possible that their servers may have been knocked down temporarily and that no one can connect to it. Not very likely, but it could happen.
Your issue is genuine, I don't know why people downvoted you. I was having the same problem, and after searching Google for a while, I found that it was my router's MTU that was causing the issue. In my case, the MTU was set to 1480, and after setting to 1468, PokémonGo started working again on my WiFi.
Your mileage may vary, though.
These links may help you: