Troubleshooting and known issues

If you cannot find your issue here, please email, including logs from the concordium-node-retrieve-logs tool.

Multiple nodes, bakers, and accounts

We do not currently support running two nodes on the same machine. When the concordium-node tool is run, while another node is already running, it will ask you if you want to stop the currently running node and start a new one.

A node can only run as one baker. A baker is by definition a member of the committee. The current committee can be obtained by querying the node via

$concordium-client consensus show-parameters --include-bakers

A node can run as a baker or not, depending on how it is started, and whether the keys it starts with are registered in the committee.

Which baker the node runs as is determined by the baker keys that it starts with (these are in the file baker-credentials.json). If a node is restarted it reloads the keys that exist at the time it starts.

Appearance of high memory consumption of the node

The Concordium node may appear to use a lot of memory, and its memory consumption may grow over time. This happens because the node internally uses the LMDB database for block and transaction storage. LMDB manages the database as a single memory-mapped file which can cause certain tools to erroneously include the whole or parts of the database file into the reported memory consumption of the process.

Node does not catch up with chain on Windows

On Windows, the Concordium node may fail to catch up with the chain when changing internet connections. It usually catches up with the chain again after few minutes. Otherwise, stop and restart the node.

Failure to catch-up on Windows might also occur, if the time in the docker virtual machine is out of sync. This can happen as a result of the machine entering sleep (even if the node is not running at the time). The following may be indications that this has occurred:

  • Errors in the log such as ERROR: External: Error importing block: ResultEarlyBlock (or any other error involving ResultEarlyBlock).

  • Timestamps of messages in the log do not match the system time. (Note, the log timestamps are given in the UTC timezone; you may need to add or subtract a few hours to convert to your local time.)

To fix this, shutdown the node, restart your computer (or just restart Docker Desktop), and then restart the node.

If the problem persists, it could be that the system time is set incorrectly. (This is especially likely if you observe negative times on the Concordium Network Dashboard.) To fix this, open Date & time settings and select Sync now under Synchronize your clock. You may have to restart the node as described above after synchronizing your clock.

(Note: it may be possible to resynchronize the virtual machine’s clock without having to restart it. This can be done by stopping and restarting the Time synchronization integration service for the docker virtual machine using Hyper-V Manager.)

Node on Windows fails to bootstrap with Docker Desktop 3.1.0

When running your node on Windows, it might fail to bootstrap. In that case, it will not get any peers and does not catch up to the chain or at least not to the full fin length. You can check both e.g. on the network dashboard. Furthermore, the log will show the following entries:

ERROR: Can't connect to the desired address
INFO: Attempting to bootstrap
INFO: No peers at all - retrying bootstrapping

The issue only occurs with the latest Docker Desktop version 3.1.0. The node works fine with when running with earlier Docker versions. However, since Docker from version 3.0.0 and upwards automatically updates to the latest version when restarting, we strongly recommend to install Docker Desktop, which comes with Docker Engine version 19.03.13.

  • To check, which Docker Desktop version you have installed, right-click the Docker Desktop system tray icon (i.e. the whale carrying a stack of containers) and choose “About Docker Desktop”. It should say (or lower).

  • To check, which Docker Engine version you have installed, run docker version in your terminal. It should say Version: 19.03.13 (or lower).

We suggest the following workaround:

  • Run concordium-node-stop.

  • Run concordium-node-reset-data (optional).

  • Uninstall your current Docker software.

  • Download Docker Desktop version

  • Install Docker Desktop version

  • When the installation is completed, make sure Docker is running.

  • Whenever you are prompted that a new Docker Desktop is available, chose “Skip This Build” or “Remind me later”. Never click “Install Update”.

  • Run concordium-node.

Your node should now catch up to the full fin length and eventually get peers assigned. Whenever you restart your node, remember to not update to the newest version.

Docker error port already in use

The node may fail starting with the error Error starting {..} proxy: listen tcp{PORT}: bind: address already in use, which can be remedied by using a different {PORT} than the default used by the node.

The ports used by the node are as follows:

  • 8888, the port for P2P networking, which can be set with --listen-node-port

  • 8082, the port used by internal backend, which can be set with --listen-middleware-port

  • 10000, the gRPC port, which can be set with --listen-grpc-port

When changing the mappings above the docker container must be stopped, reset, and started again. To reset the container either use concordiumn-node-reset-data or run the following in a terminal

$docker rm concordium-client

Special language characters in the Windows client

Depending on the code page of the Windows machine, the concordium-client might not print all special language characters in account names correctly. Instead it replaces unknown characters with a question mark. In such a case, you can either use the account address for client commands instead of the incomplete name, check the name mapping file or change the code page of the terminal to utf-8 by running chcp 65001.

Supported ID document types and countries

For issuing a real-world identity in the mobile wallet Concordium ID, i.e. an identity based on a physical ID document, 3rd parties identity issuer Notabene and identity verifier Onfido are invoked. For a list of supported ID document types and countries, please visit supported ID documents.

The previously described identity issuing option can be selected in the process of creating a new identity using Notabene on the New Identity Verification screen. Note that with option Notabene development test identities can be issued, which are not verified against physical ID documents.

Inconsistency with numbers on ID documents

When issuing an identity in the mobile wallet Concordium ID with identity provider Notabene, which is based on a Danish ID document, the personal identity number might be included as document number in the issued identity instead of the actual ID document number. Danish ID documents (e.g. passport or driver’s license) have a document number field and a personal code number field for the CPR number. The number from the document number field should be included as document number in the issued identity. Inconsistencies may be observed where the CPR number is used instead. The issue is reported to identity provider Notabene.

Performance issues in mobile wallet on Android phones

Performance issues, e.g. long processing times, might occur when running the mobile wallet Concordium ID on a low end Android phone. Processing delays might not be indicated by appropriate waiting screens.

Robustness issues with shielded transfer in mobile wallets

When executing multiple shielded transfers or unshielding flows in the mobile wallets within a very short period of time, inconsistencies might be observed. Those robustness issues can be circumvented by waiting a few seconds between such transactions.

Support & Feedback

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