Login Details Problem - User Synchronization

Hello Sir!

We have a big problem about this plugin called "User Synchronization". After successfully installing the plugin to our two wordpress sites, most of the users (almost all) copied to the "Subsite" cannot logged in using their Master Site Account.

We know the users were copied but the password is wrong. We have already try to delete all users and re-sync them again but no luck.

This is the login error.

ERROR: The password you entered for the username (someuser name here) is incorrect.