Webasto Unite MID OCPP 1.6J Connection Closes with 1006 / ClosedChannelException #1896

Tschniaefae · 2025-12-05T21:59:13Z

Tschniaefae
Dec 5, 2025

I need help diagnosing a persistent connection issue between a Webasto Unite MID 22kW wallbox and my Steve 3.9.0 server. The wallbox establishes a WebSocket connection and sends its initial OCPP messages, but the session is immediately closed by the wallbox with a WebSocket error 1006 (ClosedChannelException). As a result, the station remains stuck in Pending status and is not counted in the dashboard.

I have followed the standard setup guides meticulously. Any insight into this vendor-specific behavior or compatibility issue would 8000 be greatly appreciated.

Technical Environment

Steve Version: 3.9.0 (from the official ZIP)

Steve Database Registration Status: Pending

Server: Raspberry Pi 5, Raspberry Pi OS Lite 64-bit, running via Docker Compose.

```
Wallbox: Webasto Unite MID 22kW
```

Wallbox Firmware: v3.166.0-1.0.148.0-v7.0.28 (as reported in BootNotification)

OCPP Protocol: 1.6J (JSON over WebSockets)

Connection Security: Security Profile 0 (unsecured ws://)

Configuration Details

Steve OCPP WebSocket Endpoint: ws://[server-ip]:8180/steve/websocket/CentralSystemService/7000641623000940

Webasto Central System URL: Set exactly to the endpoint above.

Critical Webasto OCPP Parameters:
  AuthorizeRemoteTxRequests: true
  AuthorizationCacheEnabled: false
  AuthorizationKey: (Not set, for Security Profile 0)

What I Have Already Tried

Verified network connectivity and firewall rules (port 8180 is open).

Confirmed the WebSocket URL is correct, including the full path with ChargeBox ID.

Ensured OCPP 1.6J is selected on both ends.

Set AuthorizeRemoteTxRequests to true and cycled power on the wallbox.

Changed the station's registration_status in Steve from Accepted to Pending and back.

The wallbox sends a Heartbeat if the connection stays alive long enough, confirming basic messaging works.

Logs from Steve

[INFO ] ... [chargeBoxId=7000641623000940, ...] Connection is established
[INFO ] ... [chargeBoxId=7000641623000940, ...] Received: [2, "...", "BootNotification",{
"chargePointModel": "UNITE",
"chargePointVendor": "WEBASTO",
"chargePointSerialNumber": "7000641623000940",
"firmwareVersion": "v3.166.0-1.0.148.0-v7.0.28",
"meterSerialNumber": "22202418",
"meterType": "MID",
"chargeBoxSerialNumber": "7000641623000940"
}]
[INFO ] ... The boot of the chargebox '7000641623000940' with registration status 'Optional[ACCEPTED]' is acknowledged.
[INFO ] ... Sending: [3,"...",{"status":"Accepted","currentTime":"...","interval":14400}]
[INFO ] ... [chargeBoxId=7000641623000940, ...] Received: [2,"...","FirmwareStatusNotification",{"status":"Installed"}]
[INFO ] ... [chargeBoxId=7000641623000940, ...] Sending: [3,"...",{}] # Steve's empty response
[ERROR] ... [chargeBoxId=7000641623000940, ...] Transport error
[WARN ] ... [chargeBoxId=7000641623000940, ...] Connection is closed, status: CloseStatus[code=1006, reason=Session Closed]
java.nio.channels.ClosedChannelException: null

Specific Questions

Has anyone successfully integrated a Webasto Unite MID with this firmware series and Steve 3.9.0?

The ClosedChannelException occurs immediately after Steve sends the empty {} response to the FirmwareStatusNotification. Is this a known compatibility issue? Could the Webasto firmware expect a different response structure?

Are there any workarounds, such as disabling certain OCPP features on the wallbox or applying a patch to Steve?

Thank you for your time and expertise. I'm happy to provide any additional logs or information.

goekay · 2025-12-09T13:11:35Z

goekay
Dec 9, 2025
Maintainer

hey there, did you look at the logs of the station?

[INFO ] ... [chargeBoxId=7000641623000940, ...] Sending: [3,"...",{}] # Steve's empty response

maybe the empty object {} is the offending part in this response.

close status code 1006 is not a regular one. it signals that there was no close frame, meaning it was closed abnormally.

0 replies

yyildirim01 · 2026-07-07T20:59:18Z

yyildirim01
Jul 7, 2026

@Tschniaefae I have the same issue even with the standard software version, were you able to figure out the 1006 issue?

Firmware version v2.99.11-1.0.109.0

Webasto unite

0 replies

Navigation Menu

Uh oh!

Uh oh!

Webasto Unite MID OCPP 1.6J Connection Closes with 1006 / ClosedChannelException #1896

Uh oh!

{{title}}

Uh oh!

Replies: 2 comments

Uh oh!

{{title}}

Uh oh!

Uh oh!

{{editor}}'s edit

{{editor}}'s edit

Uh oh!

Uh oh!

{{title}}

Uh oh!

Uh oh!

{{editor}}'s edit

{{editor}}'s edit

Uh oh!

Select a reply

Uh oh!

Uh oh!

Uh oh!

Webasto Unite MID OCPP 1.6J Connection Closes with 1006 / ClosedChannelException #1896

Uh oh!

Tschniaefae Dec 5, 2025

Replies: 2 comments

Uh oh!

Uh oh!

goekay Dec 9, 2025 Maintainer

Uh oh!

Uh oh!

yyildirim01 Jul 7, 2026

Tschniaefae
Dec 5, 2025

goekay
Dec 9, 2025
Maintainer

yyildirim01
Jul 7, 2026