description: Frequently asked questions FAQ and answers for troubleshooting Pantheon
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# Troubleshooting
If Pantheon is not working as expected, here are some things to check or try.
## Supplied Genesis Block Does Not Match Stored Chain Data
If you get a `Supplied genesis block does not match stored chain data` error, use the genesis file which matches the genesis block
of the data directory or use the [`--data-path`](../Reference/Pantheon-CLI-Syntax.md#data-path) option to specify a different data directory.
## Host Not Authorized
If you are receiving a `Host not authorized` error when attempting to access the JSON-RPC API, ensure [`--host-whitelist`](../Reference/Pantheon-CLI-Syntax.md#host-whitelist)
includes the host from which you are sending the RPC or `*`.
## Peers Fail to Connect
If nodes are not communicating, ensure the [required ports are open](https://docs.pantheon.pegasys.tech/en/stable/Configuring-Pantheon/Networking/Configuring-Ports/).
If your nodes are running in AWS, check you have appropriate `SecurityGroups` to allow access to the required ports.
Check the [enode URLs](../Configuring-Pantheon/Node-Keys.md#enode-url) specified for [bootnodes](../Configuring-Pantheon/Networking#bootnodes)
or [static nodes](../Configuring-Pantheon/Networking/Managing-Peers.md#static-nodes) match the enode URLs
displayed when the remote nodes are started.
## Mining
Check blocks are being created. On mining nodes, log messages indicate blocks are being created.
```bash
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 blocks are being imported.
```bash
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.
If blocks are not being created in [Clique](../Consensus-Protocols/Clique.md#extra-data) or [IBFT 2.0](../Consensus-Protocols/IBFT.md#extra-data) networks,
ensure the validator addresses in the genesis file match running nodes.
## Transactions Not Being Mined
If a transaction is added to the [transaction pool](../Using-Pantheon/Transactions/Transaction-Pool.md)
and the transaction hash returned but the transaction is never being mined, check the [`--min-gas-price`](../Reference/Pantheon-CLI-Syntax.md#min-gas-price)
option on mining nodes. If the `gasPrice` on a [transaction](../Using-Pantheon/Transactions/Transactions.md)
is lower than the `min-gas-price` for the mining node, the transaction will never be mined.
In [free gas networks](../Configuring-Pantheon/FreeGas.md), [`--min-gas-price`](../Reference/Pantheon-CLI-Syntax.md#min-gas-price) must be set to 0.
## Genesis Milestone
Not including a sufficient milestone in the genesis file can lead to unexpected and inconsistent behaviour without
specific errors. Ensure a sufficient milestone is included in the genesis file (for example, `constantinoplefixblock`).
When using Java 9 or later, the following error message may be displayed on startup and does not affect the operation of Pantheon:
```
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by org.bouncycastle.jcajce.provider.drbg.DRBG (file:/Users/madelinemurray/pantheon/build/distributions/pantheon-1.1.2-SNAPSHOT/lib/bcprov-jdk15on-1.61.jar) to constructor sun.security.provider.Sun()
WARNING: Please consider reporting this to the maintainers of org.bouncycastle.jcajce.provider.drbg.DRBG
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
```
To stop the message being displayed, add the following to the environment: