diff --git a/state/validation.go b/state/validation.go
index 3836fffd..9bb912da 100644
--- a/state/validation.go
+++ b/state/validation.go
@@ -120,7 +120,7 @@ func CentralConfigValidator(cfg *CentralCfg) error {
 		routerPrefixes := make(map[netip.Prefix]struct{})
 		for _, p := range router.Prefixes {
 			if _, ok := routerPrefixes[p.GetPrefix()]; ok {
-				return fmt.Errorf("router %s has duplicate prefix %s", router.Id, p)
+				return fmt.Errorf("router %s has duplicate prefix %s", router.Id, p.GetPrefix())
 			}
 			routerPrefixes[p.GetPrefix()] = struct{}{}
 		}
@@ -129,7 +129,7 @@ func CentralConfigValidator(cfg *CentralCfg) error {
 				client := cfg.GetClient(peer)
 				for _, cp := range client.Prefixes {
 					if _, ok := routerPrefixes[cp.GetPrefix()]; ok {
-						return fmt.Errorf("router %s has duplicate prefix %s (provided by client %s)", router.Id, cp, client.Id)
+						return fmt.Errorf("router %s has duplicate prefix %s (provided by client %s)", router.Id, cp.GetPrefix(), client.Id)
 					}
 					routerPrefixes[cp.GetPrefix()] = struct{}{}
 				}
diff --git a/state/validation_test.go b/state/validation_test.go
index 41fea72f..fadcac48 100644
--- a/state/validation_test.go
+++ b/state/validation_test.go
@@ -244,3 +244,21 @@ func TestCentralConfigValidator_AnycastPrefix(t *testing.T) {
 	}
 	assert.NoError(t, CentralConfigValidator(cfg))
 }
+
+func TestCentralConfigValidator_DuplicatePrefixMessage(t *testing.T) {
+	prefix := PrefixHealthWrapper{&StaticPrefixHealth{Prefix: netip.MustParsePrefix("10.5.0.0/24")}}
+	cfg := CentralCfg{Routers: []RouterCfg{{NodeCfg: NodeCfg{Id: "r1", Prefixes: []PrefixHealthWrapper{prefix, prefix}}}}}
+	assert.EqualError(t, CentralConfigValidator(&cfg), "router r1 has duplicate prefix 10.5.0.0/24")
+
+	addr := []netip.Addr{netip.MustParseAddr("10.0.0.5")}
+	cfg = CentralCfg{
+		Routers: []RouterCfg{{NodeCfg: NodeCfg{Id: "r1"}}},
+		Clients: []ClientCfg{
+			{NodeCfg: NodeCfg{Id: "phone", Addresses: addr}},
+			{NodeCfg: NodeCfg{Id: "laptop", Addresses: addr}},
+		},
+		Graph: []string{"r1, phone, laptop"},
+	}
+	ExpandCentralConfig(&cfg)
+	assert.ErrorContains(t, CentralConfigValidator(&cfg), "router r1 has duplicate prefix 10.0.0.5/32 (provided by client")
+}