LND Anchor Output Errors - Fix Reserve and CPFP Fee Bumping Issues

What Are LND Anchor Outputs?

Anchor outputs are small outputs added to commitment transactions in LND, allowing fee bumping via CPFP after broadcast. Errors arise when anchor reserves are insufficient or CPFP fails.

Common Error Messages

• insufficient funds for anchor reserve
• anchor sweep: no UTXOs available
• channel force-closed due to low anchor reserve
• CPFP anchor transaction rejected by mempool

Fix: Check Anchor Reserve

# View wallet balance and anchor reserve
lncli walletbalance

# LND requires ~10000 sats per anchor channel as reserve
# If balance is low, deposit more on-chain funds

Fix: CPFP Fee Bumping

# Bump fee for a pending anchor sweep
lncli wallet bumpclosetxfee --chan_point <funding_txid:0> --conf_target 6

# Or specify sat/vbyte directly
lncli wallet bumpclosetxfee --chan_point <txid:0> --sat_per_vbyte 20

Fix: Disable Anchors (Not Recommended)

# In lnd.conf (only for new channels)
[protocol]
protocol.no-anchors=true

# WARNING: disables CPFP fee bumping on force-close

Prevention

• Keep at least 30000 sats on-chain per anchor channel
• Monitor wallet balance with alerting (Prometheus + Alertmanager)
• Use lncli pendingchannels to spot anchor issues early

Stuck on LND anchor issues? DM on Nostr for a free diagnosis.