Skills that are registered in DA are not showing.

Summary

Trying to update the skills in DA but Skills are not showing.

Content

Upon entering my DA I have encountered an error saying 'There was an unexpected error processing the request. Please contact Oracle Support Services.' and there are no skill listed in my DA so I tried to add a skill then an error occurred  too saying 'You can't register skill ****_HCM.DA, version 3.1 with this digital assistant. The same invocation name is already used by another registered skill.'. I tried to add another DA but still got that kind of error. Any solution on this prob? How can I update my skills in DA?