diff --git a/client/config.go b/client/config.go
index 25682f6a..eea948a0 100644
--- a/client/config.go
+++ b/client/config.go
@@ -22,7 +22,7 @@ const (
 var (
 	ErrInvalidDNSResolver        = errors.New("invalid DNS resolver specified. Required format is {proto}://{ip}:{port}")
 	ErrInvalidDNSResolverPort    = errors.New("invalid DNS resolver port")
-	ErrInvalidClientOAuth2Config = errors.New("invalid OAuth2 configuration, all fields are required")
+	ErrInvalidClientOAuth2Config = errors.New("invalid oauth2 configuration: must define all fields for client credentials flow (token-url, client-id, client-secret, scopes)")
 
 	defaultConfig = Config{
 		Insecure:       false,