We are experiencing an issue when a user tries to set up a WarTag for the first time. While we fix this, you can use the workaround.
Workaround:
*After you set a WarTag, you won't be able to change it at this point. In the future, you will be able to purchase a rename token from the shop. When we get to release, most likely all of you will receive a free token(or we will reset all WarTags) to change your WarTag.
We are sorry for the inconvenience.