Our app has been fixed. Streamable http transport isn’t working now. Switching to SSE transport helps to restore app functionality. Please consider that Streamable Http should be temporary disabled.
Had the same problem exactly. No code changes and suddenly not working overnight. Changed all the code not to use FastMCP decorators and works. Would love to have my previous version working
Any resolution here? Have been facing the same issue
same. broken for ~15 hours.
Just adding to the chorus, also running into this issue, even when rolling back code to yesterday.
Gonna throw my hat into the “error in message stream” pile as well…. 
Also getting the same error after re-deploying my server code
+1 Getting “Error in message stream”. Same code is working previously. Seems like a bug shipped to custom connector on OpenAI side.
Same error here with my custom MCP server. No code change, all working yesterday, not now 
“funny thing” is that from AI builder it is still working fine.
Happening to me as well, it’s working fine from the mcp inspector.
Hi everyone, sorry about this. We pushed a fix around 6:55am PST today and are just waiting for it to deploy. Will keep this thread updated!
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It seems to be working now. Not getting “Error in message stream” message.
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Still not working for me.
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Same here for me it’s been 2 1/2 days ive been getting that message
Has been working for me for about 5 hours now.
Hi everyone, thank you for your patience. We can now confirm that this issue has been resolved.
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