Unable to send follow-up message to cloud agent

Where does the bug appear (feature/product)?

Background Agent (GitHub, Slack, Web, Linear)

Describe the Bug

I’m unable to send a follow-up message to a kicked off cloud agent. I keep getting Error sending message: Error: HTTP error! status: 404 when trying to send a message. Is anyone else running into this? I tried logging out and logging back in and this is happening both within the cursor IDE and cursor web.

Steps to Reproduce

Create cloud agent, let it run
Send follow-up message

Expected Behavior

Can send follow-up message

Operating System

MacOS

Version Information

Version: 2.7.0-pre.133.patch.0 (Universal)
VSCode Version: 1.105.1
Commit: d4e60f0ae12e228fa5fbe3151ff53838a82b86a0
Date: 2026-03-25T05:47:52.636Z
Build Type: Stable
Release Track: Nightly
Electron: 39.8.1
Chromium: 142.0.7444.265
Node.js: 22.22.1
V8: 14.2.231.22-electron.0
OS: Darwin arm64 25.3.0

Does this stop you from using Cursor

Yes - Cursor is unusable

Hi @rzidv,

Thanks for reporting this. The 404 error on follow-up messages suggests the backend can’t locate the cloud agent session when you try to send a follow-up. There are a few possible causes for this, and to narrow it down, I’ll need a bit more info.

Could you share the following from one of the failing agents?

  1. The bcId – you can find this in the URL when viewing the agent (it looks like bc-xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx)

  2. Is the agent still running when you try to follow up, or has it already completed?

  3. Does this also happen on the stable build? Since you’re on Nightly (2.7.0-pre.133.patch.0), it would help to know if this is a nightly-specific regression

With the bcId I can trace the exact failure on our end and determine what’s going wrong.

Hi @mohitjain!

  1. bc-8847c73a-06d8-4703-a4ac-525ec8a51fbe
  2. The agent has finished the initial task but I want it to make some changes and do some manual testing
  3. I’m not sure if it also happens on stable, I can test this later today but its also happening for me in the web agent UI so I would assume it would also be broken in stable?

Thank you for the help!

Hi bump on this! I’m still running into this issue

Hi Ryan!

Thanks for the details. I traced the bcId through our backend logs and confirmed the issue. Your follow-up messages are reaching the backend, but the processing is hitting an internal error that’s causing the 404. This is a bug on our end, not anything wrong with your setup.

I’ve flagged this with our cloud agents team for investigation. In the meantime, as a workaround, you could try creating a new cloud agent for the additional changes rather than sending a follow-up to the completed one.

I’ll update this thread once we have more info from the team.

Sounds good, thank you!