diff --git a/apps/gooyal_oauth2/validators.py b/apps/gooyal_oauth2/validators.py
index 4a1f0d7..bb83c13 100755
--- a/apps/gooyal_oauth2/validators.py
+++ b/apps/gooyal_oauth2/validators.py
@@ -221,11 +221,11 @@ class OAuth2Validator(BaseOAuth2Validator):  # pylint: disable=w0223
         id_token = token.get("id_token", None)
         if id_token:
             id_token = self._load_id_token(id_token)
-        headers = deepcopy(dict(request.headers))
-        for header in dict(request.headers):
-            if type(headers[header]) not in [str, bool, int, float, tuple, list]:
-                print(f'unserializable header: {header} -> {headers[header]}')
-                headers.pop(header)
+        headers = {}
+        for header, value in dict(request.headers).items():
+            if type(value) in [str, bool, int, float, tuple, list]:
+                print(f'unserializable header: {header} -> {value}')
+                headers[header] = value
 
         return AccessToken.objects.create(
             user=request.user,