General advise: First press Cluster on your files, then use the “lookup” button on the clusters. Don’t use the “Scan” button (for acoustic fingerprinting with AcoustID) unless you have to (e.g. your files have absolutely no meaningful metadata, in which case neither cluster nor lookup will work well). See also the following threads:
If this fails you can also manually load albums from the MusicBrainz website into Picard, see: