The user is unable to edit his created dashboard, As an admin I tried to change the owner from his name to name is also not working
Group: 'DL-GTN-Connectivity_Operations' does not exist, or user 'Teju Naik' does not have permission to share with this group.
Recently our IT team deleted the mentioned group.

The owner has given the above group Shared with VIEW permission causing an issue.
Please, anyone, help how can I solve this issue, there are a lot of private dashboards that have been created.