You can't access Sky Sports via the TVGO app, you need to downlaod the Sky Sports app and log in using your VM credentials.
Although to clarify this, TV Go does contain the schedule for all the Sky Sports channels and links to them.
The difference is, that the links are - rather than opening the streams within TV Go - prompts to open the Sky Sports app separately.
Welcome to the community
Sorry to hear you're having issues accessing Sky Sports. To access your Sky Sports subscribed channels, you'll need to download the Sky sports app as advised and sign in with your Virgin Media details, where it advises Virgin Media UK customer to sign in on the home page.
Please let us know if you have any further issues accessing your Sky Sports subscribed channels and we'll investigate this further.