Since Pokemon Go has been release on Tuesday July 5, 2016. Their has been server issues that has made the game unbearable to get online. Since then Pokemon Go developer’s created a twitter account to give support and has address this issues
Thank you for your patience. We have been working to fix the server issues. We will continue rolling out #PokemonGO to new countries soon.
— Pokémon GO (@PokemonGoApp) July 8, 2016
Still no solution for server issue but we will have to wait for upcoming updates.