Could you try this step, please:
- In the Azure portal, select Resource groups from the left-hand menu.
- Select resource-group from the list of resource groups.
- In the resource-group window, select Delete resource group from the action bar.
- In the Delete a resource group window, enter the name of the resource group to confirm the deletion.
- Select Delete to remove the resource group and all resources within it.
- Verify the resource group is no longer listed in the Resource groups window.
OR
- Try to delete the profiles in the network security perimeters
- And then delete the Network Security Perimeters
Refer this doc: https://learn.microsoft.com/en-us/azure/private-link/create-network-security-perimeter-portal#delete-a-network-security-perimeter
Kindly let us know if the above helps or you need further assistance on this issue.