LND Slow Sync or Stuck at Block Height — Fix Bitcoind Connection

LND stuck syncing, showing wrong block height, or can't connect to bitcoind? Here's how to diagnose and fix it.

Check sync status

# Check LND's current block height vs network
lncli getinfo | python3 -c "
import json, sys
d = json.load(sys.stdin)
synced = d.get('synced_to_chain', False)
synced_graph = d.get('synced_to_graph', False)
block_height = d.get('block_height', 0)
print(f'Block: {block_height} | Chain synced: {synced} | Graph synced: {synced_graph}')
"

# Compare with actual chain tip
curl -s https://mempool.space/api/blocks/tip/height

Check bitcoind connection

# Test if bitcoind is reachable from LND config
cat ~/.lnd/lnd.conf | grep -E 'bitcoind|rpc|zmq'

# Test bitcoind RPC directly
bitcoin-cli -rpcuser=<user> -rpcpassword=<pass> getblockchaininfo | python3 -c "
import json, sys
d = json.load(sys.stdin)
print(f'Bitcoind: {d[\"blocks\"]} blocks, progress: {d[\"verificationprogress\"]:.4f}')
"

# Test ZMQ (LND needs these)
nc -zv 127.0.0.1 28332  # zmqpubrawblock
nc -zv 127.0.0.1 28333  # zmqpubrawtx

Check LND logs for connection errors

sudo journalctl -u lnd --since '30 minutes ago' | grep -iE 'bitcoind|rpc|zmq|connect|error|chain' | tail -30

Fix: LND can't connect to bitcoind

# In ~/.lnd/lnd.conf, verify:
[Bitcoind]
bitcoind.rpchost=127.0.0.1
bitcoind.rpcuser=<your_rpc_user>
bitcoind.rpcpass=<your_rpc_pass>
bitcoind.zmqpubrawblock=tcp://127.0.0.1:28332
bitcoind.zmqpubrawtx=tcp://127.0.0.1:28333

# In ~/.bitcoin/bitcoin.conf, verify:
server=1
rpcuser=<your_rpc_user>
rpcpassword=<your_rpc_pass>
zmqpubrawblock=tcp://127.0.0.1:28332
zmqpubrawtx=tcp://127.0.0.1:28333
txindex=1

Fix: LND stuck behind many blocks

# First make sure bitcoind is fully synced
bitcoin-cli getblockchaininfo | grep 'verificationprogress'
# Should be 0.9999+

# If bitcoind is synced but LND is stuck, restart LND
sudo systemctl restart lnd

# Watch it catch up
watch -n 10 'lncli getinfo | python3 -c "import json,sys; d=json.load(sys.stdin); print(d[\"block_height\"])"'

Need sync/connection help? $9

I debug LND-bitcoind connection issues, ZMQ config, and sync problems. USDT TRC-20.

→ Service page