DMF error "INVALID FUNCTION NAME" while doing Modify target mapping in AX 2012(Custom method added to base entity)

I have created a custom generate method in existing employee entity for DMF . The method what i created was generateNino(). But while modifying target mapping in Target entity form i was getting infolog with following error.


"Invalid function name: generateNino"


Solution:

Just restart the AOS services and try to run Modify target mapping.