From 3:00 pm on April 12, 2021 (JST), we had a problem in the server. We sincerely apologize for the inconvenience. If you couldn't make or receive calls or you found the notification delay, we would like you to try again because the instability is now resolved.
For your information, the server problem is now resolved, however, some users may find connection to the service is instable. It's because the access to the service and the server load is rapidly increased.
Besides, you may find the instability in incoming and outgoing calls. We are now trying to solve the problem and we'll notify you as soon as the service is restored.
We apologize for the inconvenience and really appreciate your patience.