diff --git a/internal/bcd/ast/default.go b/internal/bcd/ast/default.go
index 673bfc5a8..9b3488adf 100644
--- a/internal/bcd/ast/default.go
+++ b/internal/bcd/ast/default.go
@@ -229,7 +229,7 @@ func (d *Default) ToParameters() ([]byte, error) {
 		}
 		return []byte(fmt.Sprintf(`{"int":%s}`, value)), nil
 	}
-	return nil, nil
+	return nil, errors.Wrapf(consts.ErrValidation, "missing value for parameter %s", d.GetName())
 }
 
 // Docs -
diff --git a/internal/views/michelson_storage_view.go b/internal/views/michelson_storage_view.go
index 51b69c284..24e574811 100644
--- a/internal/views/michelson_storage_view.go
+++ b/internal/views/michelson_storage_view.go
@@ -5,6 +5,7 @@ import (
 	"context"
 	stdJSON "encoding/json"
 
+	"github.com/baking-bad/bcdhub/internal/bcd/consts"
 	"github.com/baking-bad/bcdhub/internal/models/contract"
 	"github.com/baking-bad/bcdhub/internal/noderpc"
 	"github.com/pkg/errors"
@@ -42,7 +43,7 @@ func NewMichelsonStorageView(impl contract.ViewImplementation, name string, stor
 
 func validateJSONFragment(name string, data []byte) error {
 	if !stdJSON.Valid(data) {
-		return errors.Errorf("invalid michelson storage view: %s is not valid JSON", name)
+		return errors.Wrapf(consts.ErrValidation, "invalid michelson storage view: %s is not valid JSON", name)
 	}
 	return nil
 }