MCP connection refused and timeout errors

An MCP connection error means the client could not reach the server. For local servers the process failed to start; for remote servers the HTTP endpoint was unreachable, timed out, or was misaddressed. Verify the transport, address, port, and that the server is running.

A stdio server that cannot start (bad command, missing binary) produces a connection failure. Confirm the command works when run directly and the transport config matches.

Connection refused on HTTP means nothing is listening at the address, or a firewall blocks the port. A timeout means the host is reachable but not answering. Verify the URL, port, and that the service is running behind any proxy.