diff --git a/services/web/server/src/simcore_service_webserver/invitations/_client.py b/services/web/server/src/simcore_service_webserver/invitations/_client.py
index 4ca20894b0e..2822be94316 100644
--- a/services/web/server/src/simcore_service_webserver/invitations/_client.py
+++ b/services/web/server/src/simcore_service_webserver/invitations/_client.py
@@ -84,7 +84,7 @@ async def extract_invitation(
     ) -> ApiInvitationContent:
         response = await self.client.post(
             url=self._url_vtag("/invitations:extract"),
-            json={"invitation_url": invitation_url},
+            json={"invitation_url": f"{invitation_url}"},
         )
         return ApiInvitationContent.model_validate(await response.json())