I have unused Virtual Network 'youtubepower' in Resource Group named 'Group'. Its the only one resource in the group. When i trying to delete it gives an error like on the picture below:
Alternatively when i trying to delete the whole resource group it shows follows:
The same result if i set VNet settings to point-to-site or site to site. Also i have found if i select to move another resource to the group it says that there is a magical 'videotopwebsite' which prevent the operation. I believe that 'videotopwebsite' is unix-machine deleted long time ago (a year ago) but i don't see anything about it 'All Resources' section. Few more pictures: