# QBFT Consensus Troubleshooting

**Last Updated:** 2026-01-31  
**Document Version:** 1.0  
**Status:** Active Documentation

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**Date**: 2025-12-20  
**Issue**: Blocks not being produced despite validators being connected

## Current Status

### ✅ What's Working
- All validator keys deployed correctly
- Validator addresses match genesis extraData
- Network connectivity is good (10 peers connected)
- Services are running
- Genesis extraData is correct (5 validator addresses in QBFT format)
- QBFT configuration present in genesis (`blockperiodseconds: 2`, `epochlength: 30000`)
- RPC now enabled on validators (with QBFT API)

### ❌ What's Not Working
- **No blocks being produced** (still at block 0)
- **No QBFT consensus activity** in logs
- Validators are looking for "sync targets" instead of producing blocks
- No QBFT-specific log messages (no "proposing block", "QBFT consensus", etc.)

## Root Cause Analysis

The critical observation: **Validators are trying to sync from peers instead of producing blocks**.

In QBFT:
- Validators should **produce blocks** (not sync from others)
- Non-validators sync from validators
- If validators are looking for sync targets, they don't recognize themselves as validators

## Configuration Verified

### Genesis Configuration ✅
```json
{
  "config": {
    "qbft": {
      "blockperiodseconds": 2,
      "epochlength": 30000,
      "requesttimeoutseconds": 10
    }
  },
  "extraData": "0xf88fa00000000000000000000000000000000000000000000000000000000000000000f869941c25c54bf177ecf9365445706d8b9209e8f1c39b94c4c1aeeb5ab86c6179fc98220b51844b749354469422f37f6faaa353e652a0840f485e71a7e5a8937394573ff6d00d2bdc0d9c0c08615dc052db75f825749411563e26a70ed3605b80a03081be52aca9e0f141c080c0"
}
```

Contains 5 validator addresses:
1. `0x1c25c54bf177ecf9365445706d8b9209e8f1c39b`
2. `0xc4c1aeeb5ab86c6179fc98220b51844b74935446`
3. `0x22f37f6faaa353e652a0840f485e71a7e5a89373`
4. `0x573ff6d00d2bdc0d9c0c08615dc052db75f82574`
5. `0x11563e26a70ed3605b80a03081be52aca9e0f141`

### Validator Configuration ✅
- `miner-enabled=false` (correct for QBFT)
- `sync-mode="FULL"` (correct)
- Validator keys present at `/keys/validators/validator-*/`
- Node key at `/data/besu/key` matches validator key
- RPC enabled with QBFT API

## Possible Issues

### 1. Besu Not Recognizing QBFT Consensus
- **Symptom**: No QBFT log messages, trying to sync instead of produce
- **Possible cause**: Besu may not be detecting QBFT from genesis
- **Check**: Look for consensus engine initialization in logs

### 2. Validator Address Mismatch
- **Status**: ✅ Verified - addresses match
- All validator addresses in logs match extraData

### 3. Missing Validator Key Configuration
- **Status**: ⚠️ Unknown
- Besu should auto-detect validators from genesis extraData
- But config file has no explicit validator key path

### 4. Network Synchronization Issue
- **Status**: ✅ Verified - peers connected
- All validators can see each other (10 peers each)

## Next Steps

1. **Check QBFT Validator Set**: Query `qbft_getValidatorsByBlockNumber` via RPC to see if validators are recognized
2. **Check Consensus Engine**: Verify Besu is actually using QBFT consensus engine
3. **Review Besu Documentation**: Check if there's a required configuration option for QBFT validators
4. **Check Logs for Errors**: Look for any silent failures in consensus initialization

## Applied Fixes

1. ✅ Enabled RPC on validators with QBFT API
2. ✅ Verified all validator keys and addresses
3. ✅ Confirmed genesis extraData is correct
4. ✅ Verified network connectivity

## Status

**Still investigating** - Validators are connected but not producing blocks. The lack of QBFT consensus activity in logs suggests Besu may not be recognizing this as a QBFT network or the nodes as validators.