Password Update - April 15, 2020
To increase account security, we’ll be updating Battle.net on April 15 to allow your account password length to exceed 16 characters, the previous limit. However, it is crucial to note that Diablo III does not support passwords that exceed 16 characters.
We are already planning ahead to resolve this issue as quickly as possible, and plan to have a patch out that addresses this on June 9.
If your password exceeds 16 characters following this update, you will be able to log into and play Diablo III through Battle.net, but will not be able to log into Diablo III in-game at the account login screen until June 9 .
Thank you for your patience as we work on a solution. We’ll see you in Sanctuary!Fuente