This alert might occur when you try to get album artwork for songs in your library. To resolve this:
- Open iTunes.
- Click Store > Sign Out (this will sign you out of the your iTunes Store account).
- Quit iTunes.
- Reopen iTunes.
- Click Store > Sign In and then sign in to your iTunes Store account.
- Try to select the songs and choose Advanced > Get Album Artwork again.
If this does not resolve the issue, disable third-party services and startup items by booting the computer to a selective startup. Then, follow steps in iTunes for Windows: Troubleshooting security software issues to rule out security software as a cause.
This is an excerpt from this: