EDIT 3 - 3 Februrary, 2022 05:57 (UTC): The new build has now been reviewed and we are rolling it out to everyone. The update should be available to everyone shortly. If the update is not showing for you, please follow the instructions in these articles:
Android - I can't update my game (Android)
EDIT 2 - 2 Februrary, 2022 16:00 (UTC): We now have identified what caused the issue, but the fix will need to be rolled out in the form of an app update. As this process usually takes quite some time, we do not expect this issue to be resolved within the next hours. We will keep you posted as progress is made.
EDIT - 2 February, 2022 08:00 (UTC): No players are currently able to access the Ninja Tower Event. We hope to have new builds released as soon as possible to fix the issue. Thank you for your patience and understanding in the meantime.
February 2, 2022 at 07:00 (UTC+0): There is currently a known issue in the game causing players to be unable to access the Ninja Tower.
We are currently investigating this issue and trying to get it resolved as soon as we can.
We will update with any news on the issue as soon as possible. Our apologies for any inconvenience caused by this!