Can you confirm the problem is with adding your iCloud email to Windows/Mac or adding your Virginmedia account to your iPhone? If iCloud then Virginmedia’s mail settings won’t have any affect on that as they’re not the email provider - Apple is. If you’re experiencing problems with your VM broadband or Mobile settings & the iCloud account is indicating this is the cause of your problem then let me know the following:
Which email app/program are you using? If Windows Mail did you all the app to set up the account for you or did you create it manually? Have you turned on 2-step authentication in your Apple ID account? If yes did you create an app specific password which is entered instead of the account password? Is there any error message when you sync the account? Do you use any antivirus software?
Is iCloud email now working? If not then is there any error message? I had to create an app specific password to use iCloud, the auto setup worked best but I still needed to enter the app specific password. I use the inbuilt Mail app.