By default, if a user incorrectly enters their password 3 times when they are trying to log in, their user account will be made inactive. In other words, the Status of their account will be changed to Under Construction. For the user to be able to log in again, you need to change the Status of their account to Live. This option can be disabled or the number of attempts changed within the System Configuration section of Squiz Matrix.

For more information, refer to the System Configuration manual.