A change was deployed to the Wikitech config 2019-04-15T23:16 UTC which prevents users from logging into the wiki with a username that differs in case from the 'cn' value for their developer account.
This change is not expected to cause problems for most users, but there may be some people who have historically entered a username with mismatched case (for example "bryandavis" instead of "BryanDavis") and relied on MediaWiki and the LdapAuthentication plugin figuring things out. This will no longer happen automatically. These users will need to update their password managers (or brains if they are not using a password manager) to supply the username with correct casing.
The "wrongpassword" error message on Wikitech has been updated with a local override to help people discover this problem. See https://phabricator.wikimedia.org/T165795 for more details.
Bryan, on behalf of the Cloud Services team