caddyserver/caddy · error

ambiguous site definition: %s

Error message

ambiguous site definition: %s

What it means

Error "ambiguous site definition: %s" thrown in caddyserver/caddy.

Source

Thrown at caddyconfig/httpcaddyfile/httptype.go:588

	}
	autoHTTPS := []string{}
	if ah, ok := options["auto_https"].([]string); ok {
		autoHTTPS = ah
	}

	for i, p := range pairings {
		// detect ambiguous site definitions: server blocks which
		// have the same host bound to the same interface (listener
		// address), otherwise their routes will improperly be added
		// to the same server (see issue #4635)
		for j, sblock1 := range p.serverBlocks {
			for _, key := range sblock1.block.GetKeysText() {
				for k, sblock2 := range p.serverBlocks {
					if k == j {
						continue
					}
					if slices.Contains(sblock2.block.GetKeysText(), key) {
						return nil, fmt.Errorf("ambiguous site definition: %s", key)
					}
				}
			}
		}

		var (
			addresses []string
			protocols [][]string
		)

		for _, addressWithProtocols := range p.addressesWithProtocols {
			addresses = append(addresses, addressWithProtocols.address)
			protocols = append(protocols, addressWithProtocols.protocols)
		}

		srv := &caddyhttp.Server{
			Listen:          addresses,
			ListenProtocols: protocols,

View on GitHub (pinned to 50e54ee279)

Solutions

1. Make the site addresses unambiguous: combine the conflicting site blocks or give each site a distinct address so routes are not merged ambiguously.

When it happens

Trigger: Thrown at caddyconfig/httpcaddyfile/httptype.go:588 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of caddyserver/caddy@50e54ee279 (2026-08-15). Data as JSON: /api/errors/38e9e88d67f31670. Report an issue: GitHub.