14 Character password limit in Plesk Control Panel
Overview
This is a known and documented issue with Plesk, as explained in their article.
They have an arbitrary 14-character limit in the actual html field for password creation. If you had previously used our tool in your AccountCenter or requested that technical support change your password to something longer than 14 characters, you would not be able to change your password again using Plesk. The method that we use to set your passwords applies them more directly, and avoids this limit. If you would like to use the Plesk Control Panel directly to manage your password, you will need to first change your password to less than 14 characters via the AccountCenter and then set the final password in your Plesk.
TIP:
We always recommend that you use the AccountCenter to set your Plesk Administrator password so that our Support Department has a straightforward method available to log into your Control Panel.