SBT cannot find snapshots in an Artifactory maven repository

The issue was not with my sbt configuration after all, but with my repository server.

I'm using Artifactory, and the snapshots repository was configured to use "unique snapshots" by default. The filenames of these snapshots are modified as they are published to include a timestamp, which sbt 13.x doesn't seem to understand.

After changing the repository's "Maven Snapshot Version Behaviour" from "Unique" to "Nonunique", everything started to work.