From WinAmp forums: CDDB problems (Gracenote Services No Longer Work In Winamp: Reason Why Explained)
it looks like the access Winamp had to Gracenote's services has been terminated and is the reason why things have stopped working.
this was going to happen anyway as a result of the sale of Winamp and SHOUTcast in January where the deal with them was not going to be renewed (and if Winamp and SHOUTcast hadn't been bought, what you're now seeing would have happened anyway), but we weren't at all sure when things were going to stop working (as all that was known is it might be sometime between the start of 2014 and early 2015).
as such until a new Winamp client is released with a Musicbrainz based solution (as we're not aiming to have a new client out until the end of the year due to the mass of work required to remove / replace the AOL / Gracenote specific parts), there's not much i can really suggest at the time on what can be done as an alternative for the Gracenote powered features.