[Auth/Connect]: Claude custom connector can't connect to Salesforce Sandbox.

[paulmcnamara-futu]

MCP client

Claude (Web)

If "Other", which client?

No response

Client version

No response

Authentication flow attempted

Authorization Code (browser)

OAuth scopes granted

api sfap_api refresh_token einstein_gpt_api

Org Type

Sandbox

Network environment

• Corporate proxy or egress filtering may apply
• VPN in use
• mTLS or custom CA certs involved
• None of the above

Endpoint configuration

https://api.salesforce.com/platform/mcp/v1-beta.2/sandbox/platform/sobject-all
https://api.salesforce.com/platform/mcp/v1-beta.2/sobjects

Token acquisition steps

Error messages

https://claude.ai/settings/connectors?&server=9de4c397-c7ef-4cbd-8dfa-481c22d703bf&step=end_error&oauth_error=unsupported_grant_type&oauth_error_description=grant%20type%20not%20supported

I have already checked the following common causes

• Incorrect audience / resource / scope parameters
• Using a Connected App instead of External Client App
• Token issued for wrong environment (e.g., login vs test domain)
• Proxy stripping auth headers
• mTLS handshake failures (cert chain/hostnames)
• Mis-typed server URL or path

What I’ve tried

After initially getting this working in a developer environment, I then tried to get the Claude AI working with a Salesforce sandbox environment. I was able to get it working with a local client but using the remote salesforce mcp server connection didn't work. Tried changing scopes, changing networks, used different users, using different solutions proposed by Claude but nothing on the server side has worked.
Tried different endpoints but it made no difference.
https://api.salesforce.com/platform/mcp/v1-beta.2/sandbox/platform/sobject-all
https://api.salesforce.com/platform/mcp/v1-beta.2/sobjects

Attachments

[HJGitDev]

We are the same issue. We are following the posted Salesforce notes: https://help.salesforce.com/s/articleView?id=platform.claude_with_connectors.htm&type=5. Any guidance on when this comes out of beta into GA?

[anaphel]

Hello, same issue here, I've tried different change in security/scope/policies but still blocked.

[dnstommy]

Look at the authorize url for the scopes. In the url below you see the scopes are:

scope=api+sfap_api+refresh_token+einstein_gpt_api

I needed to add einstein_gpt even though Salesforce said it was optional.

https://test.salesforce.com/services/oauth2/authorize?response_type=code&client_id=XXXXXXXXXXXXFgNbXlBTCGOIol4Xst4XClNo_PPJdm23kCjtCWZMgaLIbj.IZEKLXJAkVG57&redirect_uri=https%3A%2F%2Fclaude.ai%2Fapi%2Fmcp%2Fauth_callback&code_challenge=XXXXXXXXJAgXmNpvvtYfCNdblRWp_7E8ma6Z_geM&code_challenge_method=S256&state=LmNs1-T3bfEriDX6nGb1xRMkd_PyZQR_oFGZ2HvoHZc&scope=api+sfap_api+refresh_token+einstein_gpt_api&prompt=select_account

[rossbelmont]

We're working with Anthropic on a Claude-specific issue right now. I'd be curious to know if you get better or different results in Cursor, ChatGPT, etc.

[VelvetCircuit92]

Experiencing the same issue. Sandbox org connection fails silently after OAuth completes successfully in Claude Desktop v1.1.9669 (macOS).

Environment:

• MCP server URL: https://api.salesforce.com/platform/mcp/v1-beta.2/sandbox/platform/sobject-all
• OAuth scopes: api, sfap_api, refresh_token, offline_access, einstein_gpt_api
• PKCE and JWT-based access tokens enabled

Behaviour: OAuth redirects to test.salesforce.com, authorisation completes, browser briefly shows step=success in the Claude URL, then Claude displays: "Authorization with the MCP server failed." Connector does not appear in the connected servers list. No client-side error logs.

Anthropics support reference IDs: ofid_93ccbe6812d82c57, ofid_7665c2f70c0587fd.

[rossbelmont]

@VelvetCircuit92 I wonder if you can capture a screenshot of the way that it looks like it works, but then returns an error. I don't think I've seen that.

[mikeegonzales-eng]

Same. Also erroring and getting "MCP Salesforce Hosted MCP Servers (Beta): Server disconnected. "

[rossbelmont]

Hmm, again, if you could maybe capture a screenshot, that might give us some clues. I just connected to my sandbox again in my Claude account.

[mikeegonzales-eng]

@rossbelmont . Yesterday i was able to at least log into salesforce, today it's just redirecting me to "Error: No authorization code received"

[rossbelmont]

Thanks for the screenshots — that's helpful. A couple of things stand out:

First, it looks like you're using the older Claude Desktop extension, which is no longer the recommended way to connect. Second, the localhost callback URL in your setup won't work with the hosted MCP server — that's a local redirect that the Salesforce auth flow can't complete against.

We'd recommend starting fresh with our GA setup guide, which covers the current supported approach for Claude and other clients: https://developer.salesforce.com/docs/platform/hosted-mcp-servers/guide/client-connection-overview.html

Let us know how it goes.