I recall an old version of vBulletin doing this to me, and it frustrated me enough that I wrote a very similar article. I had a very long password generated for my account, which had moderator permissions. But when I tried to login, no dice. After a few back-and-forths, I came to the frustrating realization that the "Set Password" screen had a limit, whereas the frontend "Login" page had a separate, or no, limit.<p>I totally get the need to have a maxlength on your password input, since you don't want to be processing KBs of data each time a user logs in. But, one, make it reasonable (1000 is fine), and two, make it consistent wherever passwords are entered.