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Troubleshooting

How to start Desktop Modeler without plugins​

You can start Desktop Modeler with the --disable-plugins flag.

How to obtain Desktop Modeler logs​

Depending on your operating system, you can find Desktop Modeler logs in different places:

%APPDATA%\camunda-modeler\logs

To produce logging output, you can also run Desktop Modeler from the command line.

I cannot connect to Zeebe​

You try to connect (i.e., to deploy) to a remote Zeebe instance, and Desktop Modeler tells you it "cannot find a running Zeebe."

To resolve this issue, check if you can connect to Zeebe through another client, i.e., zbctl. If that works, further debug your Zeebe connection. If that does not work, resolve the general connection issue first.

Resolve a general Zeebe connection issue​

You try to connect to Zeebe from both Desktop Modeler and zbctl, and neither of them works. General connection failures can have a couple of reasons:

The (remote) Zeebe instance is not reachable​

Ensure your computer has access to the (remote) network.

The connection to Zeebe happens through a proxy​

Inspect the connection to understand if it can be established.

Secure connections to Zeebe require HTTP/2 over TLS with protocol negotiation via ALPN. Ensure your proxy supports these features and does not forcefully downgrade the connection to HTTP/1.

Debug Zeebe connection issues​

You can connect to Zeebe via zbctl or another API client. However, connecting through Desktop Modeler fails.

Secure connection to Zeebe fails​

When connecting securely to Camunda 8 SaaS, Camunda 8 Self-Managed, or a standalone Zeebe instance (via https endpoint URL), Desktop Modeler tries to establish a secure connection. In the process, it strictly validates the server certificates presented against well-known certificate authorities. Failure to connect may have several reasons:

The (remote) endpoint is not configured for secure connections​

Ensure you properly configured the remote endpoint.

The (remote) endpoint presents an untrusted certificate​

Inspect the connection to understand which certificates are being returned by the server.

Ensure you configure Desktop Modeler for custom SSL certificates.

If intermediate signing authorities sign the server certificate, ensure the remote endpoint serves both server and intermediate certificates to Desktop Modeler.

How can I provide a custom SSL certificate?​

You configured a custom SSL certificate in your (remote) Zeebe endpoint and want Desktop Modeler to accept that certificate.

The app strictly validates the remote server certificate trust chain. If you use a custom SSL server certificate, you must make the signing CA certificate known to Desktop Modeler, not the server certificate itself.

Desktop Modeler reads trusted certificate authorities from your operating systems trust store. Installing custom CA certificates in that trust store is recommended for most users. Alternatively, you may provide custom trusted CA certificates via the --zeebe-ssl-certificate flag.

How can I get details about a secure remote connection?​

You can use the following command to retrieve information about HTTP/2 over TLS support (ALPN) and certificates provided by a remote endpoint:

> openssl s_client -alpn h2 -connect google.com:443 -servername google.com
[...]
---
Certificate chain
 0 s:/CN=*.google.com
   i:/C=US/O=Google Trust Services LLC/CN=GTS CA 1C3
 1 s:/C=US/O=Google Trust Services LLC/CN=GTS CA 1C3
   i:/C=US/O=Google Trust Services LLC/CN=GTS Root R1
 2 s:/C=US/O=Google Trust Services LLC/CN=GTS Root R1
   i:/C=BE/O=GlobalSign nv-sa/OU=Root CA/CN=GlobalSign Root CA
---
[...]
---
New, TLSv1/SSLv3, Cipher is AEAD-CHACHA20-POLY1305-SHA256
Server public key is 256 bit
Secure Renegotiation IS NOT supported
Compression: NONE
Expansion: NONE
ALPN protocol: h2
SSL-Session:
    Protocol  : TLSv1.3
    Cipher    : AEAD-CHACHA20-POLY1305-SHA256
    Session-ID:
    Session-ID-ctx:
    Master-Key:
    Start Time: 1687516295
    Timeout   : 7200 (sec)
    Verify return code: 0 (ok)
---

How can I debug log gRPC / Zeebe communication?​

You can also start Desktop Modeler with gRPC logging turned on to get detailed logging output on communication to Zeebe:

set DEBUG=* && set ZEEBE_NODE_LOG_LEVEL=DEBUG && set GRPC_VERBOSITY=DEBUG && set GRPC_TRACE=all && "Camunda Modeler.exe"

Desktop Modeler does not start on Ubuntu 24 / modern Linux​

Modern Linux operating systems introduce restrictions on user namespaces, a sandboxing (isolation) mechanism Modeler uses. You may see an error message when you start the application:

$ ./camunda-modeler
[46193:1114/170934.837319:FATAL:setuid_sandbox_host.cc(163)] The SUID sandbox helper binary was found, but is not configured correctly. Rather than run without sandboxing I'm aborting now. You need to make sure that [...]/camunda-modeler-[...]-linux-x64/chrome-sandbox is owned by root and has mode 4755.
zsh: trace trap (core dumped)  ./camunda-modeler

To remedy this, configure your system to allow sandboxing by creating an AppArmor profile, or review this issue for an in-depth explanation of available options. If you don't have the necessary permissions to permit sandboxing, you may choose to disable the sandbox, though this is not recommended.

Other questions?​

Head over to the Modeler category on the forum to receive help from the community.