Migrations currently only work between Alby Hubs that are both based on LDK.
Migrating from Alby Cloud (LDK) to Start9 (LND) is not yet supported, unfortunately.
Start9 (LDK) should work however. But I haven't tried it myself yet. https://app.gitbook.com/o/uiUeRqI074apbV0PWsyf/s/TESBxdA83bO5QfV5RnQM/alby-hub/faq-alby-hub/how-can-i-migrate-alby-hub-to-a-different-machine