diff --git a/core/corehttp/gateway_handler.go b/core/corehttp/gateway_handler.go
index 40e16363170..34950f1211f 100644
--- a/core/corehttp/gateway_handler.go
+++ b/core/corehttp/gateway_handler.go
@@ -393,7 +393,7 @@ func (i *gatewayHandler) serveFile(w http.ResponseWriter, req *http.Request, nam
 			// Fixes https://github.com/ipfs/go-ipfs/issues/7252
 			mimeType, err := mimetype.DetectReader(content)
 			if err != nil {
-				http.Error(w, "cannot detect content-type", http.StatusInternalServerError)
+				http.Error(w, fmt.Sprintf("cannot detect content-type: %s", err.Error()), http.StatusInternalServerError)
 				return
 			}