Skip to main content
Gumloop connects to MCP servers from its cloud, not from your computer. A server that works in Claude Desktop or Cursor can still fail in Gumloop because firewalls, IP allowlists, and OAuth redirect rules see a different caller.

​
Find your error

​
OAuth is grayed out

Gumloop enables OAuth 2.0 only when it finds the OAuth metadata the server publishes. If that check is blocked or redirected, OAuth is grayed out.
  1. Allow Gumloop through your firewall. If the server filters by IP, allow all of Gumloop’s static egress IPs. A 403 hides the OAuth metadata.
  2. Use the exact endpoint URL from the provider’s docs, including https:// and any trailing slash. Some servers only answer on /mcp/.
  3. Self-hosted servers: check the app’s public “site URL” setting. If it uses http:// or an internal hostname, Gumloop can’t follow the OAuth links.
  4. If the provider requires your own OAuth app, create one, add both Gumloop redirect URLs, then choose OAuth 2.0 (Custom Client) and enter the client ID and secret.
  5. Remove the server and add it again so Gumloop reruns the check.

​
OAuth sign-in fails or loops

The OAuth provider is rejecting Gumloop as a client. Ask whoever manages it to:
  1. Allow both redirect URLs:
  2. Allow Dynamic Client Registration (DCR) or Client ID Metadata Documents (CIMD) from hosted clients, not only desktop apps. If they can’t, register an OAuth app for Gumloop and use OAuth 2.0 (Custom Client).
If OAuth worked before and broke after reconnecting, the provider likely allows only api.gumloop.com. Add api.gumstack.com too.

​
Tools won’t load

The server connected, but Gumloop couldn’t list its tools.
  • API key: retype it by hand. Trailing spaces, line breaks, or curly quotes from copy and paste break the header. Enter extra headers as Header-Name: value.
  • Transport: the server must use Streamable HTTP or SSE over HTTPS. localhost and STDIO aren’t supported. Expose a local server with a tunnel such as Cloudflare Tunnel or ngrok, or use Managed Tunnels on Enterprise.
  • Session header: if a proxy sits in front of a stateful server, make sure it doesn’t strip Mcp-Session-Id.
  • Gateway in front of the server: for Cloudflare Access, AWS API Gateway, or Azure API Management, add its credential as an Access Gate on a proxied MCP.
After you fix the cause, reopen the connector to retry. For a proxied MCP, click Fetch New Tools.

​
Hosted MCP won’t create or deploy

For admins using Hosted MCPs.

Custom, proxied, and hosted MCP

Which type to use

Custom MCP servers

URLs, headers, and OAuth