Unable to establish Plane MCP Integration with Supergrok/xAI Connectors

Summary of troubleshooting shown below, generated from chat with my Grok instance.

Sequence of Events

1. Initial Recommendation: User requested setup instructions for Plane MCP alongside existing connectors in Grok. I provided the standard OAuth flow using https://mcp.plane.so/http/mcp via grok.com/connectors → Custom Connector.

2. First Attempt (OAuth):

   • The Plane OAuth consent screen loaded successfully (GitHub SSO session active).
   • You selected the “” workspace and approved read/write permissions.
   • Grok’s Custom Connector popup displayed “Complete authentication in the popup window...” and remained stuck in a hung “Connecting...” state indefinitely.

3. Troubleshooting Steps Applied:

   • Recommended deleting the partial connector, clearing browser cache/cookies, using Incognito mode, and full logout/re-login (including GitHub SSO on Plane).
   • Suggested switching to the PAT (Personal Access Token) method to bypass browser OAuth.

4. Second Attempt (PAT):

   • Used the dedicated endpoint https://mcp.plane.so/http/api-key/mcp.
   • Grok again showed the same hung authentication window.
   • No prompt appeared for entering the API key or headers (Authorization: Bearer ... and X-Workspace-Slug).
   • Behavior identical to the OAuth attempt.

Key Observations

• The Plane OAuth consent screen functions correctly.
• The hang consistently occurs on the Grok side during the post-OAuth or PAT handshake phase.
• GitHub SSO on your Plane account may contribute to redirect/cookie conflicts.
• No error message is displayed beyond the indefinite loading state.
• Other MCP connectors in your Grok account function normally, isolating the issue to Plane integration.

Reference Links for Similar / Related Issues

• Plane MCP Server Official Documentation: https://developers.plane.so/dev-tools/mcp-server
• Plane MCP Server Repository (for bug report): https://github.com/makeplane/plane-mcp-server/issues
• General Grok / xAI Remote MCP Documentation: https://docs.x.ai/developers/tools/remote-mcp
• Common MCP OAuth / Custom Connector Hanging Issues (Claude & others):
  • https://github.com/anthropics/claude-code/issues/40102 (browser stuck in re-login loop)
  • https://github.com/anthropics/claude-code/issues/52565 (OAuth tokens fail to persist)
  • General MCP connection troubleshooting: https://openclaw-ai.net/en/troubleshoot/mcp-server-connection