We have confirmed the following bugs in League of Heroes.

Details
The following error message "Error code: 100" is displayed when accessing "League of Heroes".

Maintenance period
From around 12:29 a.m. on May 29

To correct this issue, emergency maintenance of League of Heroes is being conducted.
Please note that you will not be able to move to League of Heroes during the maintenance.
We will report on the progress as soon as it is made.

The following is an update on the issue.
The fix for this issue has been completed.
The emergency maintenance of League of Heroes has been completed and League of Heroes is now available for normal use.

Outbreak Period
May 29 12:00 - May 29 13:38

We apologize for any inconvenience this may have caused to our customers.