why error throws when try to open skills & Qualification page through my client groups

Summary:

when try to check Skills and qualification through my client groups this error is coming:

Cannot invoke "java.util.Map.get(Object)" because the return value of "java.util.Map.get(Object)" is

Content (please ensure you mask any confidential information):

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):