# Cloud MCP Error: SSE error: Non-200 status code (400)

**URL:** <https://community.penpot.app/t/cloud-mcp-error-sse-error-non-200-status-code-400/10532>\
**Category:** Ask the community\
**Tags:** mcp\
**Created:** [April 29, 2026, 7:22am UTC](https://community.penpot.app/t/cloud-mcp-error-sse-error-non-200-status-code-400/10532 "2026-04-29T07:22:36Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![GwynnBleiidd](https://dub1.discourse-cdn.com/flex017/user_avatar/community.penpot.app/gwynnbleiidd/32/10367_2.png) [@GwynnBleiidd](https://community.penpot.app/u/GwynnBleiidd)\
**Post date:** [April 29, 2026, 7:22am UTC](https://community.penpot.app/t/cloud-mcp-error-sse-error-non-200-status-code-400/10532/1 "2026-04-29T07:22:36Z")

</div>

Hi, I’m trying to use MCP Server via the cloud version at design.penpot.app/mcp/stream, but two systems are already telling me it’s unavailable—`Error: SSE error: Non-200 status code (400)`

I’ve tried Qwen Studio and Open WebUI

Is this a restriction because I’m using the free version?

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**Author:** ![carolina.portugal](https://dub1.discourse-cdn.com/flex017/user_avatar/community.penpot.app/carolina.portugal/32/36_2.png) [@carolina.portugal](https://community.penpot.app/u/carolina.portugal)\
**Post date:** [April 29, 2026, 7:24am UTC](https://community.penpot.app/t/cloud-mcp-error-sse-error-non-200-status-code-400/10532/2 "2026-04-29T07:24:23Z")

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Hi @GwynnBleiidd, the MCP is also available for the Penpot free version. Can you give me more information on what is going on?

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<div class="post-metadata">

**Author:** ![GwynnBleiidd](https://dub1.discourse-cdn.com/flex017/user_avatar/community.penpot.app/gwynnbleiidd/32/10367_2.png) [@GwynnBleiidd](https://community.penpot.app/u/GwynnBleiidd)\
**Post date:** [April 29, 2026, 7:44am UTC](https://community.penpot.app/t/cloud-mcp-error-sse-error-non-200-status-code-400/10532/3 "2026-04-29T07:44:50Z")

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Actually, not very many, but let’s give it a try

Qwen Studio—I add a server and immediately run into an error

 ![image](https://europe1.discourse-cdn.com/flex017/uploads/penpot/original/2X/e/e199d914bb446d087e2f9857af4c77264a1ada98.png)

Oh, and I can’t upload more than one image, so I’ll just have to describe it in words)

Open WebUI—a little better; the validation passes when adding. But when I try to communicate, it already reports issues - Failed to connect to MCP server ‘penpot’

Of course, I’ll try some more advanced tools tonight, like Codex, Claude Code, and extensions for VS Code

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**Author:** ![juan.delacruz](https://dub1.discourse-cdn.com/flex017/user_avatar/community.penpot.app/juan.delacruz/32/12_2.png) [@juan.delacruz](https://community.penpot.app/u/juan.delacruz)\
**Post date:** [April 29, 2026, 7:49am UTC](https://community.penpot.app/t/cloud-mcp-error-sse-error-non-200-status-code-400/10532/4 "2026-04-29T07:49:03Z")

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Hi @GwynnBleiidd 🙂

You’re probably **not doing anything fundamentally wrong** , but:

- either authentication is missing

- or (more likely) the clients you’re using don’t fully support MCP over SSE

If you can share how you configured the server in Open WebUI (headers + auth), I can point out exactly what’s off.

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<div class="post-metadata">

**Author:** ![GwynnBleiidd](https://dub1.discourse-cdn.com/flex017/user_avatar/community.penpot.app/gwynnbleiidd/32/10367_2.png) [@GwynnBleiidd](https://community.penpot.app/u/GwynnBleiidd)\
**Post date:** [April 29, 2026, 8:02am UTC](https://community.penpot.app/t/cloud-mcp-error-sse-error-non-200-status-code-400/10532/5 "2026-04-29T08:02:46Z")

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> [@juan.delacruz](#):
>
> You’re probably **not doing anything fundamentally wrong** , but:
> 
> - either authentication is missing
> - or (more likely) the clients you’re using don’t fully support MCP over SSE
> 
> If you can share how you configured the server in Open WebUI (headers + auth), I can point out exactly what’s off.

Everything worked out; I had forgotten that Qwen Studio requires a type in the JSON.

And with that object, everything started working—it was actually Google Antigravity that reminded me I had forgotten to add the type.

```auto
{
  "mcpServers": {
    "penpot": {
"type": "streamable-http",
      "url": "https://design.penpot.app/mcp/stream?userToken=token"
    }
  }
}

```