Error Message :
If an object template contains user-defined metadata, it is not possible to create new objects of that type. Investigation
(1) create UC_CUSTOM_ATTRIBUTES as described in the documentation
(2) define at least one element of user-defined metadata
(3) create the associated VARA object that defines the grouping criterion and its possible values
(4) create a template for that object (for example: Create the template 'JOBP' for Workflow objects) in either client 0 or the current client: In the Header tab of the template object: Add the metadata you defined earlier.
(5) Finally, when you create a new object of the same type (for example: JOBP), the GUI will behave as though it is processing the request, however nothing happens.
See Documenation: Administration Guide > Configuration > Settings in Variables > UC_CUSTOM_ATTRIBUTES