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Last update: December 9, 2021


If Hyperledger Besu is not working as expected, here are some things to check or try.

Supplied genesis block does not match stored chain data

If a Supplied genesis block does not match stored chain data error occurs, use the genesis file matching the genesis block of the data directory, or use the --data-path option to specify a different data directory.

Invalid block header

If a TimeStampMoreRecentThanParent | Invalid block header error occurs, the genesis file of the new node is specifying a higher blockperiodseconds than the imported chain. The imported chain makes new blocks faster than the genesis file allows and Besu rejects them with this error. This error most often occurs when importing chains from older versions of Besu.

To correct this error, decrease the blockperiodseconds in the new IBFT 2.0 genesis file or QFBT genesis file to a lower value that satisfies the block header validation.


If the error reads | TimestampMoreRecentThanParent | Invalid block header: timestamp 1619660141 is only 3 seconds newer than parent timestamp 1619660138. Minimum 4 seconds, decrease the blockperiodseconds from 4 seconds to 3 seconds to match the imported chain.

After you have updated the new genesis file, if the imported chain has a blockperiodseconds value set lower than you prefer, you can adjust it by configuring the block time on an existing IBFT 2.0 or existing QBFT network.

Host not authorized

If a Host not authorized error occurs when attempting to access the JSON-RPC API, ensure --host-allowlist includes the host you are sending the RPC from, or *.

Peers fail to connect

If nodes are not communicating, ensure the required ports are open.

If your nodes are running in AWS, check you have appropriate SecurityGroups to allow access to the required ports.

Check that the enode URLs specified for bootnodes or static nodes match the enode URLs displayed when starting the remote nodes.


Check block creation. On mining nodes, log messages indicate block creation.

2019-05-08 20:28:27.026+10:00 | pool-10-thread-1 | INFO  | IbftRound | Importing block to chain. round=ConsensusRoundIdentifier{Sequence=660, Round=0}, hash=0x759afaba4e923d89175d850ceca4b8ef81f7d9c727b0b0b8e714b624a4b8e8cc
2019-05-08 20:28:29.020+10:00 | pool-10-thread-1 | INFO  | IbftRound | Importing block to chain. round=ConsensusRoundIdentifier{Sequence=661, Round=0}, hash=0x5443e504256765f06b3cebfbee82276a034ebcc8d685b7c3d1a6010fd4acfa14

On non-mining nodes, log messages indicate importing blocks.

2019-05-08 20:28:29.026+10:00 | EthScheduler-Workers-1 | INFO  | BlockPropagationManager | Imported #661 / 0 tx / 0 om / 0 (0.0%) gas / (0x5443e504256765f06b3cebfbee82276a034ebcc8d685b7c3d1a6010fd4acfa14) in 0.000s.
2019-05-08 20:28:31.031+10:00 | EthScheduler-Workers-0 | INFO  | BlockPropagationManager | Imported #662 / 0 tx / 0 om / 0 (0.0%) gas / (0x0ead4e20123d3f1433d8dec894fcce386da4049819b24b309963ce7a8a0fcf03) in 0.000s.

To confirm the block number is increasing, use the eth_blockNumber JSON-RPC API method.

If there is no block creating in Clique or IBFT 2.0 networks, ensure the validator addresses in the genesis file match running nodes.

Transactions are not mined

If you add a transaction to the transaction pool and the transaction hash returns, but the transaction is never mined, check the --min-gas-price option on mining nodes. If the gasPrice on a transaction is lower than the min-gas-price for the mining node, the transaction will never mine.

In free gas networks, you must set --min-gas-price to zero.

Genesis milestone

Not including a milestone far enough in advance in the genesis file can lead to unexpected and inconsistent behavior without specific errors. Ensure you include a milestone that is far enough in advance in the genesis file (for example, constantinoplefixblock).

Command line options

Characters such as smart quotes and long (em) hyphens do not work in Besu command line options. Ensure quotes are not automatically converted to smart quotes, or double hyphens combined into em hyphens.


Restart Besu with the command line option --logging=TRACE and look at the log files.

Pending State Nodes not decreasing for a full node in Grafana

During fast synchronization for a full node, the Pending State Nodes count is the number of nodes yet to be downloaded, and it should change constantly. Pending State Nodes trend to 0 during fast synchronization and then goes to 0.

If the number stays constant, this could mean your node is not syncing against any peers.

In the following example the Pivot Block is 0 (zero) and the Pending State Nodes value is constant. This means the node isn’t syncing against any peers. The fact that state nodes have been downloaded means at some stage it was syncing.

Fast synchronization

The easiest solution in this scenario is to restart fast synchronization to obtain a new pivot block.

Homebrew repair

When upgrading Besu, you might get the following error:

Error: Some taps failed to update!
The following taps can not read their remote branches:
This is happening because the remote branch was renamed or deleted.
Reset taps to point to the correct remote branches by running `brew tap --repair`

This error is caused by the branch name being updated from master to main but a reference to master still remains. To fix the branch reference and repair Homebrew, use the command brew tap --repair.

Thread blocked due to lack of entropy in the system random number generator

If a thread is reported as blocked, and the top of the stack contains$RandomIO.readFully as in the following example, then the operating system is out of entropy.

2021-11-06 11:28:05.971+00:00 | vertx-blocked-thread-checker | WARN  | BlockedThreadChecker | Thread Thread[vert.x-worker-thread-2,5,main]=Thread[vert.x-worker-thread-2,5,main] has been blocked for 60387 ms, time limit is 60000 ms
io.vertx.core.VertxException: Thread blocked
        at java.base@11.0.11/ Method)
        at java.base@11.0.11/
        at java.base@11.0.11/
        at java.base@11.0.11/$RandomIO.readFully(
        at java.base@11.0.11/$RandomIO.implGenerateSeed(
        at java.base@11.0.11/

If this happens, the Besu node can become unresponsive.

The occurrence of this problem and the possible solutions are system-dependent. The issue itself is rare, but would most likely occur:

  • On Linux.
  • Using virtual machines without randomness source.
  • Early after computer startup.

The solution to this depends on the situation. A good starting point is to read about blocking random number generation in Linux. A quick, non-persistent workaround is to use the non-blocking random generator instead of the blocking one:

sudo mount /dev/urandom /dev/random -o bind

Quorum Developer Quickstart not working on Apple M1 chip

The Quorum Developer Quickstart does not currently support the Apple M1 chip. The quickstart starts up on machines that use the chip, but may show the following symptoms:

  • All JSON-RPC calls return an empty reply from the server
  • The Grafana dashboard shows no data
  • The docker ps command displays an AMD message about the containers:

    Image may have poor performance, or fail, if run via emulation
  • No logs can be downloaded

Questions or feedback? You can discuss issues and obtain free support on Hyperledger Besu chat channel.
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