Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Solva, ae, f., a city of Noricum, Inscr. Grut. 537, 1.
Hence, Solvensis, e, adj., of or belonging to Solva: Flavium Solvense (sc. oppidum), Plin. 3, 24, 27, § 146.