The Pokémon Go Battle League is the PvP part of the mobile augmented reality game. In the vast majority of cases, the PvP service is generally up and running and you can fight trainers all over the world if you have the tickets to fight them. The first thing you want to check is your internet service, and hopefully the next step is to see what's going on behind closed doors and what issues the Pokémon Go app might be having.
A great first step is to go to Pokémon Go Blog to see if they have any updates on the service. For example, they may have little hiccups in the middle of the season, like part of the serve going down for a while, or readjusting the release date for one of the four leagues. The blog on the Pokémon Go page does a great job of breaking down what's going on in the game's current events and explaining how they plan to adjust programming changes.
After that, your next step is to jump on Twitter and check out the Niantic Support Twitter account. The folks there are extremely good at letting the community know about any issues that arise with any of Niantic's games, but those who run it are exceptionally good at letting the community know about Pokémon Go-related issues. If you don't follow this Twitter page, at least bookmark it on your smartphone browser for quick access to see if there are recent articles on Battle League down and what is being done. on this subject. This statement applies to both expected and unexpected maintenance.
These are the two main ways you will have to rely on to find out Pokémon Go the Battle League is not available. Apart from these two options, you mostly want to try restarting your Pokémon Go app, checking your internet service and making sure you have a strong signal. If you were having performance issues when trying to log into the Battle League and could no longer access it, you'd better wait to fight other trainers again until you come back to a place with reliable WiFi connection.
