diff --git a/Oqtane.Server/Pages/Files.cshtml.cs b/Oqtane.Server/Pages/Files.cshtml.cs
index ab65c32c..f47ce1d2 100644
--- a/Oqtane.Server/Pages/Files.cshtml.cs
+++ b/Oqtane.Server/Pages/Files.cshtml.cs
@@ -3,6 +3,7 @@ using System.IO;
 using System.Net;
 using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Http.Extensions;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.AspNetCore.Mvc.RazorPages;
@@ -96,7 +97,7 @@ namespace Oqtane.Pages
                             }
                             else
                             {
-                                HttpContext.Response.Headers.Add(HeaderNames.ETag, etag);
+                                HttpContext.Response.Headers.Append(HeaderNames.ETag, etag);
                                 return PhysicalFile(filepath, file.GetMimeType());
                             }
                         }