I dont know what the version of Red Hat Linux is.
I changed the password for the Yosemite Backup application itself. I logged out of the Yosemite Backup application, and then logged back in with my new password with success. Note that this new password is exactly the same as the old password. Yosemite Backup seemed to allow me to change the old password to the same exact value as the new password....
I then changed the Yosemite Backup settings so the password would never expire. That is all I did. I then logged out of the Yosemite Backup application.
I then had to log back in to the Yosemite Backup application, and it did not accept the new password!! It let me in before, so why not now? Do you think there is something within the application that is not allowing me to use the same value for the new password as the old password? If so, why did it let me change it like that without any warnings, and why did it let me log back in the first time after changing it?