diff --git a/DysonNetwork.Sphere/ActivityPub/ActivityPubDeliveryService.cs b/DysonNetwork.Sphere/ActivityPub/ActivityPubDeliveryService.cs
index d761658..ed7650a 100644
--- a/DysonNetwork.Sphere/ActivityPub/ActivityPubDeliveryService.cs
+++ b/DysonNetwork.Sphere/ActivityPub/ActivityPubDeliveryService.cs
@@ -234,7 +234,7 @@ public class ActivityPubDeliveryService(
             var request = new HttpRequestMessage(HttpMethod.Post, inboxUrl);
             
             request.Content = new StringContent(json, Encoding.UTF8, "application/activity+json");
-            request.Headers.Date = DateTimeOffset.UtcNow.ToString("r");
+            request.Headers.Date = DateTimeOffset.UtcNow;
             
             var bodyBytes = Encoding.UTF8.GetBytes(json);
             using var sha256 = SHA256.Create();