diff --git b/ref_resolver.py a/ref_resolver.py
index 63a47557..d77b20af 100644
--- b/ref_resolver.py
+++ a/ref_resolver.py
@@ -745,12 +745,6 @@ class Loader:
                     ):
                         loader.idx[document[identifer]] = document
                     base_url = document[identifer]
-                else:
-                    raise ValidationException(
-                        "identifier field '{}' must be a string".format(
-                            document[identifer]
-                        )
-                    )
         return base_url
 
     def _resolve_identity(
@@ -907,13 +901,6 @@ class Loader:
                     )
             except ValidationException as v:
                 _logger.warning("loader is %s", id(loader), exc_info=True)
-                raise ValidationException(
-                    "({}) ({}) Validation error in field {}:".format(
-                        id(loader), file_base, key
-                    ),
-                    None,
-                    [v],
-                ) from v
 
         elif isinstance(document, CommentedSeq):
             i = 0