I get an error that says “status 400” when I click the DSM mailbox “Forgot My Password” link.

Your browser may be set up to not allow the pop up.  You might want to review the setting in your current browser or try using another browser. (Popular browsers are, but not limited to: Firebird, Chrome, Microsoft Edge, Brave, etc.)

You can also contact your Administrator and ask them to reset your password from the Admin Portal.