There are a few steps you can take to troubleshoot an issue with changing a group name in Active Directory:

1. Make sure you have the correct permissions assigned to you to make the changes.
2. If the group is used for restricted access, check that the group is active and all the users/members are actively part of the group.
3. Check the group’s settings on the server to see if there is anything that is causing a conflict.
4. Check the name of the group against an existing list of group names to make sure it is unique.
5. Check if any policies are blocking the change from happening.