diff --git a/endpoint.go b/endpoint.go
index cfbab0e..1dbfe44 100644
--- a/endpoint.go
+++ b/endpoint.go
@@ -286,7 +286,7 @@ func (ep *endpoint) sbJoin(sbox Sandbox, options ...EndpointOption) error {
 	ep.Lock()
 	if ep.sandboxID != "" {
 		ep.Unlock()
-		return types.ForbiddenErrorf("a sandbox has already joined the endpoint")
+		return types.ForbiddenErrorf("another container is attached to the same network endpoint")
 	}
 	ep.Unlock()
 
diff --git a/error.go b/error.go
index d31a509..4158c99 100644
--- a/error.go
+++ b/error.go
@@ -129,7 +129,7 @@ type ActiveEndpointsError struct {
 }
 
 func (aee *ActiveEndpointsError) Error() string {
-	return fmt.Sprintf("network with name %s id %s has active endpoints", aee.name, aee.id)
+	return fmt.Sprintf("network %s has active endpoints", aee.name)
 }
 
 // Forbidden denotes the type of this error