"Temporary error" when connecting from Claude to Cortext Analyst MCP

[hey-look-its-tim-dries]

Issue: Snowflake Managed MCP Server fails to connect from Claude.ai after successful OAuth

Error Message:

============
Error connecting to the MCP server. Please confirm that you have permission to access the service, that you're using the correct credentials, and that your server handles auth correctly. (McpServerError: Connected successfully but the integration may not be available right now due to a temporary error.) If this persists, share this reference with support: "f21c5bd94f2d65ef"

What works:

OAuth flow completes successfully, redirects, authenticates, and returns to Claude.ai without error

What fails:

After successful OAuth, Claude.ai cannot communicate with the MCP server
Error appears immediately after authentication completes

Configuration verified:

Redirect URI: https://claude.ai/api/mcp/auth_callback
OAUTH_USE_SECONDARY_ROLES = IMPLICIT
PRE_AUTHORIZED_ROLES_LIST is empty
Blocked roles: ACCOUNTADMIN, ORGADMIN, SECURITYADMIN
User default role set to a dedicated MCP access role
All grants verified: DATABASE, SCHEMA, MCP SERVER, SEMANTIC VIEW, WAREHOUSE
MCP Server endpoint format correct
Account URL uses hyphens not underscores

To reproduce:

Create a Snowflake managed MCP server with a CORTEX_ANALYST_MESSAGE tool
Create an OAuth security integration with Claude.ai redirect URI
Add a custom connector in Claude.ai with the server URL and OAuth credentials
Complete OAuth flow: succeeds
Attempt to use the connector: fails with the above error

Any idea what is going wrong?

Tim