diff --git a/files/nats_registration_listener.py b/files/nats_registration_listener.py
index a190beb..5170373 100644
--- a/files/nats_registration_listener.py
+++ b/files/nats_registration_listener.py
@@ -484,7 +484,7 @@ async def main():
                                                 "Accept": "application/json",
                                                 "Authorization": f"Token {NB_TOKEN}",
                                             }
-                                            patch_body = {"custom_fields": {"action_last": action_next_str, "action_next_timestamp": now_epoch}}
+                                            patch_body = {"custom_fields": {"action_last": action_next_str, "action_next_timestamp": str(now_epoch)}}
                                             _, pcode = http_patch_json(
                                                 f"{base}/api/dcim/devices/{dev_id}/",
                                                 patch_body,
@@ -544,7 +544,7 @@ async def main():
                                             "Accept": "application/json",
                                             "Authorization": f"Token {NB_TOKEN}",
                                         }
-                                        patch_body = {"custom_fields": {"action_last": action_next_str, "action_next_timestamp": now_epoch}}
+                                        patch_body = {"custom_fields": {"action_last": action_next_str, "action_next_timestamp": str(now_epoch)}}
                                         _, pcode = http_patch_json(
                                             f"{base}/api/dcim/devices/{dev_id}/",
                                             patch_body,