RFEM troubleshooting

Setting the connection up is on Connecting RFEM. This page is for when it does not work.

Each state below has its own address, so Dlubal CALC can send you straight to the one that applies: /docs/rfem/troubleshooting#rfem-not-running is the section for that blocker and nothing else.

First: which link of the chain is broken

Three programs have to agree, and each one can fail on its own:

Dlubal CALC (browser)Reaches the connector on localhost 8083

Dlubal-Connector (your machine)Answers, and is paired with your account

RFEM 6 (your machine)Running, no modal dialog open

Important

The green dot next to RFEM means the connector answered. It does not mean RFEM is connected. The connector is a separate program that keeps running after you close RFEM, and it answers perfectly well while RFEM is not there at all.

The quickest way to see the real state: open http://localhost:8083/rfem-info in a browser tab. {"rfem_version":"","rfem_license":""} means the connector is fine and RFEM has never reported itself to it. Do not use /health for this, it returns 200 with an empty body and says nothing about RFEM.

RFEM is not installed

Blocker: rfem_not_installed

No RFEM 6 installation was found on the machine running the connector.

Install RFEM 6, or pair the connector on the machine that has it. The connector and RFEM have to be on the same machine: the connector talks to RFEM through a local interface, not over the network.

RFEM is not running

Blocker: rfem_not_running

RFEM6.exe is not running. Open RFEM 6 and the state clears by itself, usually within a few seconds. Nothing needs restarting.

Blocker: rfem_modal_dialog

Warning

An open dialog in RFEM, even a harmless one asking you to confirm something, stops RFEM from answering at all. The assistant looks broken and the cause is a window waiting for a click.

Switch to RFEM, close the dialog, and ask again. Worth checking first whenever RFEM is clearly running and everything still times out.

The component is starting

Blocker: mcp_starting

A start or restart is in flight. This phase is bounded: wait, and it resolves.

First-time setup is still installing

Blocker: mcp_installing

The connector installs a Python component into RFEM's own Python on first use, and that takes minutes rather than seconds. It resolves by itself. Nothing is broken.

Nothing is serving the connection

Blocker: mcp_down

RFEM is running, but no component is answering for it. Restart the connector.

If it comes back, look at the version line in Settings → MCP servers. An outdated component that keeps being adopted from an earlier session is the usual reason a restart helps for a while and then does not.

The component stopped answering

Blocker: mcp_unresponsive

The component accepts connections but no longer answers them, which is a different failure from being down and needs the same fix: restart the connector.

RFEM is not listening on its interface port

Blocker: grpc_unreachable

The component is up and RFEM is running, but RFEM is not answering on the port the component uses. Restart RFEM.

This is the one state where restarting RFEM rather than the connector is the right move.

No Dlubal API key

Blocker: api_key_missing

Without a Dlubal API key the component is never started at all. Enter your key in the Dlubal CALC settings, then let the connector start it.

Everything is up but nothing has run yet

Blocker: not_proven

A warm-up state, not a fault. Send one request and it clears.

The browser is blocking localhost

Chrome 142 and later ask for permission before a page on calc.dlubal.com may talk to localhost. Denied, the connector looks unreachable while nothing is wrong with it.

Example: the connector is running, http://localhost:8083/rfem-info answers when you open it directly in a tab, but Dlubal CALC still reports it as not reachable.

Allow "Local network access" for calc.dlubal.com in the site settings and reload. This is a browser permission, not a missing connector, and no amount of restarting will change it.

"Not reachable" that means "not paired"

A connector that is running but not paired with your account refuses the request. Depending on where that refusal surfaces it can read as "not reachable", which sends you looking for a network problem that does not exist.

If http://localhost:8083/version answers in a browser tab but Dlubal CALC insists it cannot be reached, pair it again before you touch anything else.

The version says one thing and behaves like another

The connector installs a component and then starts it. Those are two separate things and they can disagree: if a component from an earlier session is still running when the connector starts, the connector adopts it instead of starting a new one. A freshly installed version then sits on disk while the old one keeps serving.

Settings → MCP servers shows both on one line, for example Dlubal-Connector 2.28.8 · MCP 1.0.11. The second number is the one that is running. When they disagree the number turns amber and the connector restarts the component onto the installed version by itself, usually within a couple of minutes.

Example: an answer tells you a capability "is not available in your RFEM version", next to a green dot. Usually an outdated component rather than anything to do with RFEM: it never offered the tool the answer tried to use, so the model explained the gap by guessing.