getting error while creating the user in user administration in portal

Hi folks,

i am unable to create the user in user administration in portal due to the following error,

could you please help regarding this issue

"Current user has user creation permissions in the UME, but cannot create users in the back-end system (data source). The original and possibly untranslated message was: "No active writeable datasource found for user creation, check your Persistence Configuration.".