The error message "Login failed" appears when attempting to log in

Your session may have timed out. Try returning to [ DLsite ], and attempt to log in again.

An issue with the browser cache or cookies may also be causing the issue. See [ How can I clear the temporary Internet (cached) files? ] and [ How to delete cookies ] for details on how to clear the cache, and delete cookies.
Finally, you cannot log in by opening the login page from a bookmark.
In this case, please register [ DLsite ] under your bookmarks, and proceed to log in from there.