diff --git a/js/libtextsecure.js b/js/libtextsecure.js
index d76c1466..28f63b0f 100644
--- a/js/libtextsecure.js
+++ b/js/libtextsecure.js
@@ -36516,7 +36516,7 @@ var TextSecureServer = (function() {
                 // (workaround for ids too large for Javascript numbers)
                 var match = response.location.match(this.attachment_id_regex);
                 if (!match) {
-                    throw new Error('Received invalid attachment url');
+                    throw new Error('Received invalid attachment url: ' + response.location);
                 }
                 return ajax(response.location, {
                     type        : "PUT",
diff --git a/libtextsecure/api.js b/libtextsecure/api.js
index 053adb26..ba2e4fdf 100644
--- a/libtextsecure/api.js
+++ b/libtextsecure/api.js
@@ -333,7 +333,7 @@ var TextSecureServer = (function() {
                 // (workaround for ids too large for Javascript numbers)
                 var match = response.location.match(this.attachment_id_regex);
                 if (!match) {
-                    throw new Error('Received invalid attachment url');
+                    throw new Error('Received invalid attachment url: ' + response.location);
                 }
                 return ajax(response.location, {
                     type        : "PUT",