diff --git a/transport/azure/azure.go b/transport/azure/azure.go
index 63ed04c5..92acfb6d 100644
--- a/transport/azure/azure.go
+++ b/transport/azure/azure.go
@@ -93,7 +93,7 @@ func (t transport) RoundTrip(req *http.Request) (*http.Response, error) {
 			Proto:         "HTTP/1.0",
 			ProtoMajor:    1,
 			ProtoMinor:    0,
-			Header:        http.Header{},
+			Header:        http.Header{"Content-Type": {"text/plain"}},
 			ContentLength: int64(body.Len()),
 			Body:          io.NopCloser(body),
 			Close:         false,
@@ -138,7 +138,7 @@ func (t transport) RoundTrip(req *http.Request) (*http.Response, error) {
 				Proto:         "HTTP/1.0",
 				ProtoMajor:    1,
 				ProtoMinor:    0,
-				Header:        header,
+				Header:        http.Header{"Content-Type": {"text/plain"}},
 				ContentLength: int64(body.Len()),
 				Body:          io.NopCloser(body),
 				Close:         false,
diff --git a/transport/fs/fs.go b/transport/fs/fs.go
index 99434a25..36973a32 100644
--- a/transport/fs/fs.go
+++ b/transport/fs/fs.go
@@ -122,7 +122,7 @@ func respNotFound(req *http.Request, msg string) *http.Response {
 		Proto:         "HTTP/1.0",
 		ProtoMajor:    1,
 		ProtoMinor:    0,
-		Header:        make(http.Header),
+		Header:        http.Header{"Content-Type": {"text/plain"}},
 		ContentLength: int64(len(msg)),
 		Body:          io.NopCloser(strings.NewReader(msg)),
 		Close:         false,
diff --git a/transport/gcs/gcs.go b/transport/gcs/gcs.go
index 2fb71330..2f3bdc4e 100644
--- a/transport/gcs/gcs.go
+++ b/transport/gcs/gcs.go
@@ -88,7 +88,7 @@ func (t transport) RoundTrip(req *http.Request) (*http.Response, error) {
 			Proto:         "HTTP/1.0",
 			ProtoMajor:    1,
 			ProtoMinor:    0,
-			Header:        http.Header{},
+			Header:        http.Header{"Content-Type": {"text/plain"}},
 			ContentLength: int64(body.Len()),
 			Body:          io.NopCloser(body),
 			Close:         false,
@@ -196,7 +196,7 @@ func handleError(req *http.Request, err error) (*http.Response, error) {
 		Proto:         "HTTP/1.0",
 		ProtoMajor:    1,
 		ProtoMinor:    0,
-		Header:        make(http.Header),
+		Header:        http.Header{"Content-Type": {"text/plain"}},
 		ContentLength: int64(len(err.Error())),
 		Body:          io.NopCloser(strings.NewReader(err.Error())),
 		Close:         false,
diff --git a/transport/s3/s3.go b/transport/s3/s3.go
index 6e69db5e..0816e8fa 100644
--- a/transport/s3/s3.go
+++ b/transport/s3/s3.go
@@ -111,7 +111,7 @@ func (t *transport) RoundTrip(req *http.Request) (*http.Response, error) {
 			Proto:         "HTTP/1.0",
 			ProtoMajor:    1,
 			ProtoMinor:    0,
-			Header:        http.Header{},
+			Header:        http.Header{"Content-Type": {"text/plain"}},
 			ContentLength: int64(body.Len()),
 			Body:          io.NopCloser(body),
 			Close:         false,
@@ -318,16 +318,14 @@ func handleError(req *http.Request, err error) (*http.Response, error) {
 		return nil, ierrors.Wrap(err, 0)
 	}
 
-	body := strings.NewReader(err.Error())
-
 	return &http.Response{
 		StatusCode:    rerr.Response.StatusCode,
 		Proto:         "HTTP/1.0",
 		ProtoMajor:    1,
 		ProtoMinor:    0,
-		Header:        http.Header{},
-		ContentLength: int64(body.Len()),
-		Body:          io.NopCloser(body),
+		Header:        http.Header{"Content-Type": {"text/plain"}},
+		ContentLength: int64(len(err.Error())),
+		Body:          io.NopCloser(strings.NewReader(err.Error())),
 		Close:         false,
 		Request:       req,
 	}, nil
diff --git a/transport/swift/swift.go b/transport/swift/swift.go
index 151eebad..8657753c 100644
--- a/transport/swift/swift.go
+++ b/transport/swift/swift.go
@@ -60,7 +60,7 @@ func (t transport) RoundTrip(req *http.Request) (resp *http.Response, err error)
 			Proto:         "HTTP/1.0",
 			ProtoMajor:    1,
 			ProtoMinor:    0,
-			Header:        http.Header{},
+			Header:        http.Header{"Content-Type": {"text/plain"}},
 			ContentLength: int64(body.Len()),
 			Body:          io.NopCloser(body),
 			Close:         false,
@@ -80,14 +80,15 @@ func (t transport) RoundTrip(req *http.Request) (resp *http.Response, err error)
 	if err != nil {
 		if errors.Is(err, swift.ObjectNotFound) || errors.Is(err, swift.ContainerNotFound) {
 			return &http.Response{
-				StatusCode: http.StatusNotFound,
-				Proto:      "HTTP/1.0",
-				ProtoMajor: 1,
-				ProtoMinor: 0,
-				Header:     header,
-				Body:       io.NopCloser(strings.NewReader(err.Error())),
-				Close:      false,
-				Request:    req,
+				StatusCode:    http.StatusNotFound,
+				Proto:         "HTTP/1.0",
+				ProtoMajor:    1,
+				ProtoMinor:    0,
+				Header:        http.Header{"Content-Type": {"text/plain"}},
+				ContentLength: int64(len(err.Error())),
+				Body:          io.NopCloser(strings.NewReader(err.Error())),
+				Close:         false,
+				Request:       req,
 			}, nil
 		}