Builder Central (Beta) shows "Failed to fetch" on the welcome screen in my Agentforce Developer Edition org.
Console: CORS preflight to
https://api.salesforce.com/platform/dx-workspaces-proxy/v1/api/workspaces-proxy/<workspaceId>/project-service/v1/projects
is blocked. The OPTIONS response is HTTP 204 with no Access-Control-Allow-Origin header.
Reproducible with curl from outside the browser for any Origin, so it is not a client-side issue.
"Connect an org" logs in successfully but never returns to the app.
Org: nexustrade-portal-dev-ed, Home Org ID 00DgK00000WFVD2. Workspace ID: b6f6c7b9-dd87-4ca5-99e9-0d74efb79d36.
I have followed the steps -
- enable data cloud - https://help.salesforce.com/s/articleView?id=data.c360_a_setup_provision.htm&type=5
- enable einstein AI from einstein setup - https://help.salesforce.com/s/articleView?id=ai.generative_ai_enable.htm&type=5
- enable agentforce -
- enable builder central
- assign permission set - Access Builder Central
- launch the builder central(beta) from setup
#Agentforce #Salesforce Developer #Data Cloud #AI
This is a server-side problem, and nothing in your org's Setup is likely to fix it. A preflight that returns 204 with no Access-Control-Allow-Origin header from
api.salesforce.com is the gateway side. Setup's CORS allowlist and CSP Trusted Sites only govern requests to your org, not to Salesforce's own API gateway. The "Connect an org" login that never returns is probably the same backend failing.
What I could confirm from the docs- Builder Central is in beta and needs the "Access Builder Central" permission set plus the Builder Central Beta feature enabled. You've done both. salesforce
- Developer Edition is supported only with Foundations or Agentforce 1 editions. salesforce
- The release notes say availability started in September 2026. The beta is only weeks old, so a rollout gap for some org types is plausible. salesforce
What I'm inferring (not verified)- A similar pattern appears in a recent CLI issue: an Agentforce Developer Edition org on an orgfarm instance got an empty 404 from an api.salesforce.com authoring endpoint. That is a different endpoint, but it suggests some api.salesforce.com services aren't reliably routed for these DE orgs. github
- The most likely cause is that the dx-workspaces-proxy service isn't provisioned or routed for your org or instance yet. Only Salesforce can fix that.
Quick checks to rule out your side (about 10 minutes)
- Setup → Company Information: confirm the edition really shows Developer Edition with Foundations or Agentforce 1.
- Data 360 Setup Home: confirm provisioning shows fully complete, not "in progress". Provisioning can lag after you enable it.
- Confirm the permission set is assigned to the exact user you're logged in as.
- Log out and back in, and use a fresh incognito window with extensions off. The curl repro makes this unlikely to help, but it's cheap.
- Also try opening Builder Central from the App Launcher rather than from Setup.
If those pass, escalate with the details you already have
- Send the endpoint, the 204 with no ACAO header, the Org ID 00DgK00000WFVD2, the Workspace ID, the timestamp, and any x-request-id header from the response.
- Use the in-app "Give feedback" link and your Trailblazer Community post. Developer Edition orgs generally have no support case entitlement, so the community post is probably your best channel.
- Ask specifically whether the workspaces proxy is enabled for your org's instance and region, and whether DE orgs created via the Agentforce signup form are in the beta cohort.
Don't build a workaround around the blocked endpoint, such as a CORS proxy or browser flags. Even if the welcome screen loaded, project creation would still depend on that same backend.
I hope you find the above information helpful. If it does, please mark it as Best Answer to help others too.
