We fixed a bug where it was impossible to change passwords via the UMC due to the UMC server not closing file descriptors properly. Please check if an update might fix the problem.
Problem:
Changing password failed. The reason could not be determined. In case it helps, the raw error message will be displayed: . Errorcode 20: The new password could not be set.
Solution:
In Microsoft AD a user password may be changed only once a day by default password policy
Setting minimal password age=0 in the Policy it works.