Pokémon GO developer Niantic has confirmed that it has managed to fix the recent server issues that were causing occasional crashing and lagging in the immensely-popular mobile game. “Thanks for your patience, Trainers. We’re happy to report that these server issues have been resolved.” The original statement about the server issues is as follows:
“We’re currently investigating server issues that are causing occasional crashing and lagging in Pokémon GO. We apologize for the inconvenience, and we’ll provide an update as more information becomes available.”
Source: Niantic Support @NianticHelp