Information
This control defines the minimum number of characters a user password must contain. By default, the minimum passcode length is only four characters, and this is the default Exchange ActiveSync policy value applied for users not assigned to a mailbox policy if minimum password length checking is enabled. The recommended setting is 5 or more characters.
Solution
From the MobileIron console, open the Policies and Configs -> Policies view. Under the Security Policy verify that Minimum Password Length is set to 5 or more.