diff --git a/src/SecureSign.Core/Extensions/StreamExtensions.cs b/src/SecureSign.Core/Extensions/StreamExtensions.cs
index 9843925..d61f9f8 100644
--- a/src/SecureSign.Core/Extensions/StreamExtensions.cs
+++ b/src/SecureSign.Core/Extensions/StreamExtensions.cs
@@ -38,7 +38,10 @@ public static async Task CopyToFileAsync(this Stream stream, string filename)
 		{
 			using (var fileStream = File.Create(filename))
 			{
-				stream.Seek(0, SeekOrigin.Begin);
+				if(stream.CanSeek)
+				{
+					stream.Seek(0, SeekOrigin.Begin);
+				}
 				await stream.CopyToAsync(fileStream);
 			}
 		}