bug: route mcp server sse is not work

[kenneth-bro]

Current Behavior

I have an MCP server that works fine when configured within the intranet environment. However, when I configure it for external access via APISIX, it reports an error. Our current forwarding flow is:

Cloud Load Balancer (with HTTPS certificate) → APISIX (HTTP, internal network) → MCP Server (HTTP, internal network)

The access example is: https://std.test.mcp.net/mcp/common/sse, but an error occurs:
It seems the protocol is automatically downgraded to HTTP. How should I handle this issue?

Expected Behavior

connect mcp server is right

Error Logs

SSE transport: url=https://std.test.mcp.net/mcp/common/sse, headers=Accept
Error in /sse route: Error: Endpoint origin does not match connection origin: http://std.test.mcp.net/mcp/common/sse
at EventSource. (file:///Users/kenneth/.npm/_npx/5a9d879542beca3a/node_modules/@modelcontextprotocol/sdk/dist/esm/client/sse.js:82:31)
at [nodejs.internal.kHybridDispatch] (node:internal/event_target:786:20)
at EventSource.dispatchEvent (node:internal/event_target:721:26)
at file:///Users/kenneth/.npm/_npx/5a9d879542beca3a/node_modules/eventsource/dist/index.js:106:150
at dispatchEvent (file:///Users/kenneth/.npm/_npx/5a9d879542beca3a/node_modules/eventsource-parser/dist/index.js:70:24)
at parseLine (file:///Users/kenneth/.npm/_npx/5a9d879542beca3a/node_modules/eventsource-parser/dist/index.js:23:7)
at Object.feed (file:///Users/kenneth/.npm/_npx/5a9d879542beca3a/node_modules/eventsource-parser/dist/index.js:18:7)
at file:///Users/kenneth/.npm/_npx/5a9d879542beca3a/node_modules/eventsource/dist/index.js:95:46
at process.processTicksAndRejections (node:internal/process/task_queues:95:5)

Steps to Reproduce

1、build a mcp server
2、apisix config route

Environment

• APISIX version (run apisix version): 3.9.1
• Operating system (run uname -a):
• OpenResty / Nginx version (run openresty -V or nginx -V): nginx
• etcd version, if relevant (run curl http://127.0.0.1:9090/v1/server_info): 3.5.0
• APISIX Dashboard version, if relevant: 3.0.1
• Plugin runner version, for issues related to plugin runners:
• LuaRocks version, for installation issues (run luarocks --version):

[darkSheep404]

https://www.apiseven.com/blog/what-is-sse
https://www.cnblogs.com/lori/p/18757609

need config SSE related plugin ?

[kenneth-bro]

https://www.apiseven.com/blog/what-is-sse https://www.cnblogs.com/lori/p/18757609

need config SSE related plugin ?

is not work

[bfyxzls]

https://www.apiseven.com/blog/what-is-sse https://www.cnblogs.com/lori/p/18757609
need config SSE related plugin ?

is not work

ok ,I try and test,my plugin sure not work.

[Baoyuantop]

Hi @kenneth-bro, it looks like you're using APISIX version 3.9.1 and dashboard, there's no verification that they work together at this point, can you try configuring it using the admin api?