diff --git a/src/authentic2_idp_oidc/views.py b/src/authentic2_idp_oidc/views.py
index b3527fd54..21fadf2b9 100644
--- a/src/authentic2_idp_oidc/views.py
+++ b/src/authentic2_idp_oidc/views.py
@@ -688,7 +688,7 @@ def tokens_from_authz_code(request):
     if oidc_code.redirect_uri != redirect_uri:
         raise InvalidRequest(_('Parameter "redirect_uri" does not match the code.'), client=client)
     if client.access_token_duration is None:
-        expires_in = datetime.timedelta(oidc_code.session.get_expiry_age())
+        expires_in = datetime.timedelta(seconds=oidc_code.session.get_expiry_age())
         expired = None
     else:
         expires_in = client.access_token_duration