Cloud agent can't connect via api3.cursor.sh

dny_ex · November 4, 2025, 9:33pm

Where does the bug appear (feature/product)?

Background Agent (GitHub, Slack, Web, Linear)

Describe the Bug

I believe this is more of an incident, rather than a bug; but there isn’t a place to report incidents.

Also, Cloudflare is having several maintenances right now (https://www.cloudflarestatus.com/) in case that’s the trigger of the issue, but since they say that the traffic will be re-routed, perhaps the “bug” is within your internal infra that can’t connect to CF during their maintenance, or lack of resilience.

Root cause: api3.cursor.sh is unreachable. When I curl the endpoint, I get:

HTTP/2 404
“The request could not be routed”

Details:

api2.cursor.sh works fine (confirmed via network diagnostics)
api3.cursor.sh connects but Cloudflare can’t route to backend
Tested from multiple Cloudflare datacenters (LED, ARN) - same issue
Tried Google DNS (8.8.8.8) - no change
Not using VPN, firewall is off, HTTP/1.1 fallback enabled
GitHub properly connected

curl output:
➜ curl -v https://api3.cursor.sh

Host api3.cursor.sh:443 was resolved.
IPv6: (none)
IPv4: 104.18.19.125, 104.18.18.125
Trying 104.18.19.125:443…
Connected to api3.cursor.sh (104.18.19.125) port 443
ALPN: curl offers h2,http/1.1
(304) (OUT), TLS handshake, Client hello (1):
CAfile: /etc/ssl/cert.pem
CApath: none
(304) (IN), TLS handshake, Server hello (2):
(304) (IN), TLS handshake, Unknown (8):
(304) (IN), TLS handshake, Certificate (11):
(304) (IN), TLS handshake, CERT verify (15):
(304) (IN), TLS handshake, Finished (20):
(304) (OUT), TLS handshake, Finished (20):
SSL connection using TLSv1.3 / AEAD-AES256-GCM-SHA384 / [blank] / UNDEF
ALPN: server accepted h2
Server certificate:
subject: CN=api3.cursor.sh
start date: Nov 4 02:27:46 2025 GMT
expire date: Feb 2 03:27:40 2026 GMT
subjectAltName: host “api3.cursor.sh” matched cert’s “api3.cursor.sh”
issuer: C=US; O=Google Trust Services; CN=WE1
SSL certificate verify ok.
using HTTP/2
[HTTP/2] [1] OPENED stream for https://api3.cursor.sh/
[HTTP/2] [1] [:method: GET]
[HTTP/2] [1] [:scheme: https]
[HTTP/2] [1] [:authority: api3.cursor.sh]
[HTTP/2] [1] [:path: /]
[HTTP/2] [1] [user-agent: curl/8.7.1]
[HTTP/2] [1] [accept: /]

GET / HTTP/2
Host: api3.cursor.sh
User-Agent: curl/8.7.1
Accept: /

Request completely sent off
< HTTP/2 404
< date: Tue, 04 Nov 2025 21:09:37 GMT
< content-type: text/plain; charset=utf-8
< content-length: 31
< cf-ray: 999717ec8d05eff0-ARN
< cf-cache-status: DYNAMIC
< server: cloudflare
<
Connection #0 to host api3.cursor.sh left intact
The request could not be routed%

Developer console errors:
[backgroundComposer] Failed to fetch BGA metadata: ConnectError: [not_found] Error
POST https://api3.cursor.sh/… net::ERR_CONNECTION_RESET

This appears to be a Cloudflare routing configuration issue on Cursor’s infrastructure.

Steps to Reproduce

Steps are above.

Expected Behavior

Cursor client should connect to api3.cursor.sh

Operating System

MacOS

Current Cursor Version (Menu → About Cursor → Copy)

Version: 2.0.54
VSCode Version: 1.99.3
Commit: 7a31bffd467aa2d9adfda69076eb924e9062cb20
Date: 2025-11-03T22:40:44.657Z
Electron: 37.7.0
Chromium: 138.0.7204.251
Node.js: 22.20.0
V8: 13.8.258.32-electron.0
OS: Darwin x64 24.6.0

Does this stop you from using Cursor

No - Cursor works, but with this issue

deanrie · November 5, 2025, 6:40am

Hey, thanks for the report. It looks like a server-side routing issue that needs engineering attention.

I’ll pass this to the team. Your diagnostics are excellent - Cloudflare connects to api3.cursor.sh but can’t route to the backend, and the timing with Cloudflare maintenance is suspicious.

The team will review the infrastructure configuration.

In the meantime, since api2.cursor.sh works and Cursor still functions (only the Background Agent is affected), you can keep using the other features.

dny_ex · November 11, 2025, 1:24pm

Any updates on this one by any chance?

I haven’t been able to use Cloud agents in over a week

deanrie · November 12, 2025, 3:51pm

Yes, the team is actively working on this. The engineering team is investigating the Cloudflare routing issue for api3.cursor.sh.

In the meantime, other Cursor features should work normally since api2.cursor.sh is functioning correctly.

dny_ex · November 17, 2025, 8:10am

Guys pleeeeease, a solution!

The quality of work from a worktree Agent is nowhere near that of a Cloud agent.

dny_ex · November 28, 2025, 8:56pm

Any update on this one? @deanrie

deanrie · November 30, 2025, 9:38am

Thanks for the reminder. The bug with api3.cursor.sh is already tracked in the bug tracker and engineers are working on it.

The issue is with Cloudflare routing - requests to api3.cursor.sh return a 404 “The request could not be routed,” even though the connection is established.

The team is actively working on a fix. Please let me know if the problem persists after updating to the latest version.

dny_ex · November 30, 2025, 6:57pm

How does me updating to the latest Cursor version resolve this?

The problem is when trying to reach Cursor’s API https://api3.cursor.sh, even with a simple curl request.

The issue is not with the Cursor IDE client, but with Cursor’s infra setup.

This is the output of doing curl -v ``https://api3.cursor.sh:

Host api3.cursor.sh:443 was resolved.

IPv6: (none)

IPv4: 104.18.19.125, 104.18.18.125

Trying 104.18.19.125:443…

Connected to api3.cursor.sh (104.18.19.125) port 443

ALPN: curl offers h2,http/1.1

(304) (OUT), TLS handshake, Client hello (1):

CAfile: /etc/ssl/cert.pem

CApath: none

(304) (IN), TLS handshake, Server hello (2):

(304) (IN), TLS handshake, Unknown (8):

(304) (IN), TLS handshake, Certificate (11):

(304) (IN), TLS handshake, CERT verify (15):

(304) (IN), TLS handshake, Finished (20):

(304) (OUT), TLS handshake, Finished (20):

SSL connection using TLSv1.3 / AEAD-AES256-GCM-SHA384 / [blank] / UNDEF

ALPN: server accepted h2

Server certificate:

subject: CN=api3.cursor.sh

start date: Nov  4 02:27:46 2025 GMT

expire date: Feb  2 03:27:40 2026 GMT

subjectAltName: host “api3.cursor.sh” matched cert’s “api3.cursor.sh”

issuer: C=US; O=Google Trust Services; CN=WE1

SSL certificate verify ok.

using HTTP/2

[HTTP/2] [1] OPENED stream for https://api3.cursor.sh/

[HTTP/2] [1] [:method: GET]

[HTTP/2] [1] [:scheme: https]

[HTTP/2] [1] [:authority: api3.cursor.sh]

[HTTP/2] [1] [:path: /]

[HTTP/2] [1] [user-agent: curl/8.7.1]

[HTTP/2] [1] [accept: /]

GET / HTTP/2
Host: api3.cursor.sh
User-Agent: curl/8.7.1
Accept: /

Request completely sent off
< HTTP/2 404
< date: Sun, 30 Nov 2025 18:54:28 GMT
< content-type: text/plain; charset=utf-8
< content-length: 31
< cf-ray: 9a6c8db2c94f87d9-LHR
< cf-cache-status: DYNAMIC
< server: cloudflare
<

Connection #0 to host api3.cursor.sh left intact
The request could not be routed%

dny_ex · December 18, 2025, 7:49pm

Any updates?

dny_ex · December 23, 2025, 8:39am

Come on, guys….

I spend here $400 a month for two Ultra accounts. The least that you can do is fix Cloud Agents….

I haven’t been able to use them for more than a month.

dny_ex · December 26, 2025, 7:13am

Please an answer.

Your last update was a month ago, that the fix was being worked on.

deanrie · January 5, 2026, 10:05am

Hey, thanks for your patience.

I noticed something important. Your Cursor version is 2.0.54 from November 3, 2025. There have been a lot of updates since then, including changes to the Cloud Agents infrastructure.

Please try this:

Update Cursor to the latest version: Help > Check for Updates (or download it from Download · Cursor)
Restart Cursor
Try starting the Cloud Agent again

If the issue still happens after updating:

Open Developer Tools (Help > Toggle Developer Tools > Console)
Try starting the Cloud Agent
Share any new console errors

Let me know how it goes.

dny_ex · January 8, 2026, 6:04am

Forget my Cursor client IDE for a moment:

Why when I run curl -v https://api3.cursor.sh in my mac’s terminal (not Cursor’s), do I still get the error message from below:

Request completely sent off
< HTTP/2 404
< date: Thu, 08 Jan 2026 06:00:48 GMT
< content-type: text/plain; charset=utf-8
< content-length: 31
< cf-ray: 9ba97a052a2428af-AMS
< cf-cache-status: DYNAMIC
< server: cloudflare
<

Connection #0 to host api3.cursor.sh left intact
The request could not be route

?

If you want the full output, it’s in one of my previous replies.

dny_ex · January 10, 2026, 5:40pm

I updated and the Cloud Agent is still failing. Here are the errors from the Console:

And my Cursor version:

Version: 2.3.29
VSCode Version: 1.105.1
Commit: 4ca9b38c6c97d4243bf0c61e51426667cb964bd0
Date: 2026-01-08T00:34:49.798Z
Electron: 37.7.0
Chromium: 138.0.7204.251
Node.js: 22.20.0
V8: 13.8.258.32-electron.0
OS: Darwin x64 24.6.0

deanrie · January 10, 2026, 6:01pm

Hey, thanks for your patience. I need to confirm a few details so I can help correctly:

How exactly are you trying to use Cloud Agents? Can you describe your workflow?
- Are you launching it via the Slack integration?
- Via the GitHub integration?
- Directly from the IDE?
- Or are you using another method?
Are you following the official docs? If yes, can you share a link to the exact page you’re using?
Full console logs: Can you share the full output from Developer Tools (Help > Toggle Developer Tools > Console) from when you launch Cursor up to the point where you try to use a Cloud Agent? The screenshot only shows part of the errors.
Have you changed any Cursor Settings or config files related to API endpoints?

This will help the team understand the full picture and find the right fix.

dny_ex · January 11, 2026, 12:09pm

I’m attaching here a video showing my workflow from the start and with the console open:

Cursor reloading.
Initiation of a new Cloud agent.
All errors since start.
Cloud agent erroring.

I believe this will answer question 1 and 3 directly, and perhaps question 2 also. I’m literally doing the simplest way to start a new Cloud agent: via the IDE. If I’m doing it wrong, please let me know.

As for question 4, I haven’t changed anything.

dny_ex · January 12, 2026, 3:31pm

You made me update to a new version of Cursor even when I didn’t want to, and even when I told you that the problem wasn’t in the IDE, and now Cursor is unusable with this newest version…agent gets stuck all the time, can’t grep…, and the original Cloud agent issue isn’t even solved.

So instead of helping me to solve the original issue, you introduced even bigger problems that render Cursor unusable for me………………….

dny_ex · January 12, 2026, 3:35pm

And I haven’t been able to use Cloud agents in 2 months and a half even though I’m paying $500 a month for Cursor (two ultra accounts + $100 in API usage)………………….

dny_ex · January 12, 2026, 3:37pm

I’m so close to changing to Antigravity………..

dny_ex · January 23, 2026, 3:57pm