Claude Custom Connector doesn't connect

### MCP server URL

https://mcpdevtest.bluetriangle.com/mcp

### Where does the issue occur?

When auth finishes and redirects back to Claude.ai

### Transport used

streamable-http

### Client registration type

Static

### SSE only: Does your server return the expected status code for POST requests?

Not applicable (my server does not use SSE)

### When did you last reproduce this?

2026-07-31 2:10 pm

### Browser and OS

Chrome

### Describe the issue

I attempt to authenticate, I am able to log in and press the consent button. I am expecting the authentication flow to work but instead I get a "cant connect" from Claude.

### Issue details

```shell
ofid_b3a442ca7faa0b6b
```

### Expected behavior

I expect the auth flow to work as intended and for Claude to be able to connect to the MCP.

### Logs from your server

```shell

```

### Additional context

_No response_