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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"

Other questions?

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