Alby Hub v1.22.2 fails to start with Cashu/Minibits backend: error saving keyset - bucket name required

[ckosmosis]

Bug Description

Alby Hub v1.22.2 (running on Start9) fails to start when using Minibits (Cashu) as the LN backend. The error "error saving keyset: bucket name required" appears consistently on every start attempt. Two incoming payments were made but never issued to the wallet, and the Hub cannot start to claim them.

Steps to Reproduce

1. Configure Alby Hub on Start9 with Minibits (Cashu) as the LN backend at https://mint.minibits.cash/Bitcoin
2. Attempt to start Alby Hub → immediately fails with keyset error
3. Hub cannot proceed past the password screen

Logs (from unsuccessful start attempts)

2026-08-27T01:05:40-06:00 {"level":"info","msg":"Launching LN Backend: CASHU","time":"2026-08-27T07:05:40Z"}
2026-08-27T01:05:41-06:00 {"level":"info","mintUrl":"https://mint.minibits.cash/Bitcoin","msg":"Setting up cashu wallet","time":"2026-08-27T07:05:41Z"}
2026-08-27T01:05:42-06:00 {"error":"error saving keyset: bucket name required","level":"error","msg":"Failed to load cashu wallet","time":"2026-08-27T07:05:42Z"}
2026-08-27T01:05:42-06:00 {"error":"error saving keyset: bucket name required","level":"error","msg":"Failed to launch LN backend","time":"2026-08-27T07:05:42Z"}
2026-08-27T01:05:42-06:00 {"level":"error","msg":"Failed to launch LN backend: error saving keyset: bucket name required","time":"2026-08-27T07:05:42Z"}
2026-08-27T01:05:42-06:00 {"error":"error saving keyset: bucket name required","level":"error","msg":"Failed to start node","time":"2026-08-27T07:05:42Z"}

Additional Context

• Hardware: Start9 Embassy
• OS: Start9 OS
• Alby Hub version: 1.22.2
• LN Backend: Cashu (Minibits) at https://mint.minibits.cash/Bitcoin
• Minibits response: "bucket name" is not a Cashu concept — likely an Alby Hub internal issue when initiating the wallet connection
• Minibits keyset rotation: Keys rotated to new format (August 2026 migration) — possible compatibility issue with wallet implementations
• Two stuck payments (confirmed by Minibits as "paid but not yet issued"):
  • 24ebfbe07c293777ac3452da7ffe28132f9f80c213f41129b5f6a14d982fef64
  • f5ce59e0bf87e0d88c0886f4e25118957bf423a821290abe5bf8fc0990bfe336
• Current state: Cannot resolve — Hub still cannot start. Minibits says wallet should fire mint request to receive the ecash, but Hub won't start to do it.

Expected Behavior

Alby Hub should start successfully with the Cashu/Minibits backend and be able to mint received payments.

Environment

• Hardware: Start9 Embassy
• OS: Start9 OS
• Alby Hub version: 1.22.2
• LN Backend: Cashu (Minibits) at https://mint.minibits.cash/Bitcoin