diff --git a/weed/s3api/chunked_reader_v4.go b/weed/s3api/chunked_reader_v4.go
index 0d8677b20..31c711921 100644
--- a/weed/s3api/chunked_reader_v4.go
+++ b/weed/s3api/chunked_reader_v4.go
@@ -31,6 +31,7 @@ import (
 	"hash/crc32"
 	"io"
 	"net/http"
+	"strings"
 	"time"
 
 	"github.com/seaweedfs/seaweedfs/weed/glog"
@@ -138,6 +139,7 @@ func (iam *IdentityAccessManagement) newChunkedReader(req *http.Request) (io.Rea
 
 func extractChecksumAlgorithm(amzTrailerHeader string) (ChecksumAlgorithm, error) {
 	// Extract checksum algorithm from the x-amz-trailer header.
+	amzTrailerHeader = strings.ToLower(strings.TrimSpace(amzTrailerHeader))
 	switch amzTrailerHeader {
 	case "x-amz-checksum-crc32":
 		return ChecksumAlgorithmCRC32, nil
diff --git a/weed/s3api/chunked_reader_v4_test.go b/weed/s3api/chunked_reader_v4_test.go
index 3da13a71a..e386129c0 100644
--- a/weed/s3api/chunked_reader_v4_test.go
+++ b/weed/s3api/chunked_reader_v4_test.go
@@ -30,6 +30,16 @@ const (
 	defaultRegion          = "us-east-1"
 )
 
+func TestExtractChecksumAlgorithmIsCaseInsensitive(t *testing.T) {
+	got, err := extractChecksumAlgorithm("X-Amz-Checksum-Crc32")
+	if err != nil {
+		t.Fatalf("extractChecksumAlgorithm returned error: %v", err)
+	}
+	if got != ChecksumAlgorithmCRC32 {
+		t.Fatalf("extractChecksumAlgorithm() = %v, want %v", got, ChecksumAlgorithmCRC32)
+	}
+}
+
 func generateStreamingUnsignedPayloadTrailerPayload(includeFinalCRLF bool) string {
 	// This test will implement the following scenario:
 	// https://docs.aws.amazon.com/AmazonS3/latest/userguide/checking-object-integrity.html