Resolving dependencies... Error: cabal: Could not resolve dependencies: [__0] trying: blockfrost-client-core-0.6.0.0 (user goal) [__1] trying: text-1.2.5.0/installed-1.2.5.0 (dependency of blockfrost-client-core) [__2] trying: template-haskell-2.18.0.0/installed-2.18.0.0 (dependency of text) [__3] trying: servant-multipart-client-0.12.1 (dependency of blockfrost-client-core) [__4] trying: servant-multipart-0.12.1 (dependency of servant-multipart-client) [__5] next goal: lens (dependency of servant-multipart) [__5] rejecting: lens-5.2 (conflict: servant-multipart => lens>=4.17 && <5.2) [__5] trying: lens-5.1.1 [__6] next goal: blockfrost-api (dependency of blockfrost-client-core) [__6] rejecting: blockfrost-api-0.6.0.0 (conflict: lens==5.1.1, blockfrost-api => lens>=5.0 && <5.1) [__6] skipping: blockfrost-api-0.5.0.0, blockfrost-api-0.4.0.1 (has the same characteristics that caused the previous version to fail: excludes 'lens' version 5.1.1) [__6] rejecting: blockfrost-api-0.4.0.0 (conflict: blockfrost-client-core => blockfrost-api>=0.6) [__6] skipping: blockfrost-api-0.3.1.0, blockfrost-api-0.3.0.0, blockfrost-api-0.2.1.0, blockfrost-api-0.2.0.0, blockfrost-api-0.1.0.0 (has the same characteristics that caused the previous version to fail: excluded by constraint '>=0.6' from 'blockfrost-client-core') [__6] fail (backjumping, conflict set: blockfrost-api, blockfrost-client-core, lens) After searching the rest of the dependency tree exhaustively, these were the goals I've had most trouble fulfilling: lens, blockfrost-api, servant-multipart, text, blockfrost-client-core, template-haskell, base, servant-multipart-client Try running with --minimize-conflict-set to improve the error message.