TypeError: Failed to fetch during token exchange — Salesforce remote MCP connector fails post-OAuth on Desktop and browser

[rwalsh40]

MCP server URL or name

https://api.salesforce.com/platform/mcp/v1-beta.2/object-all

How are you connecting to this server?

From a custom connector URL I entered manually

Where does the issue occur?

When pressing the Connect button

When did you last reproduce this?

2026-04-09 8:06 PM EDT

Browser and OS

Chrome + Claude Desktop app on macOS

Describe the issue

After completing Salesforce OAuth consent successfully, Claude fails to complete the token exchange. Salesforce Login History confirms successful Remote Access 2.0 token issuance (Application: "Claude MCP COnnector") at exactly 8:06 PM EDT on 4/9/2026. Claude's claude.ai-web.log shows TypeError: Failed to fetch at the same timestamp — indicating Claude's connector failed to execute the token exchange POST after receiving the auth callback. Reproduces consistently across multiple days on both Claude Desktop and claude.ai browser.

Error details

"Authorization with the MCP server failed. You can check your credentials and permissions."
Error IDs: ofid_582623f12c52c3b4 / ofid_24be92767e734612 / ofid_c25e2d8904756186

Expected behavior

Connector completes authorization after Salesforce consent and token issuance, and appears as connected in the connectors panel.

Additional context

Anthropic support chat confirmed this is a persistent Desktop token exchange bug unrelated to any resolved infrastructure incident. Salesforce-side evidence (login history screenshot) available showing successful token issuance. Log evidence from claude.ai-web.log shows fetch failure at exact token exchange moment.

[localden]

Thank you for taking the time to report this — the detail you provided is genuinely helpful. We're currently triaging open MCP issues, and this one is being closed in favor of tracking it in #171, which covers the same Salesforce Hosted MCP authorization failure (OAuth succeeds but Claude reports "Authorization with the MCP server failed"). Please follow that issue for updates and add any additional context there.

In the meantime, a few reporters in #171 and #184 found that the failure can be caused by missing Salesforce-side configuration — specifically that the Hosted MCP Server needs to be activated in the Salesforce API Catalog and that the connected app may need JWT-based access tokens enabled. It may be worth double-checking those settings while we investigate the Claude-side handling.