Can you give us more information about the login issue? Are you able to sign into your normal Virgin Media cable account and use the same details for the Virgin TV Go App? Please see this link for more details. If you have been using the same details but still cannot get in, please tell us the error message and what happens exactly so we can help.
Thanks. I'll send you a Private Message so I can take some details and look deeper into this and it may be that an IT ticket is required especially if it's across different devices and they are the latest ones.