diff --git a/js/libtextsecure.js b/js/libtextsecure.js
index 28f63b0f..996ba491 100644
--- a/js/libtextsecure.js
+++ b/js/libtextsecure.js
@@ -36498,7 +36498,7 @@ var TextSecureServer = (function() {
             }).then(function(response) {
                 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        : "GET",
diff --git a/libtextsecure/api.js b/libtextsecure/api.js
index ba2e4fdf..8ae2e3b8 100644
--- a/libtextsecure/api.js
+++ b/libtextsecure/api.js
@@ -315,7 +315,7 @@ var TextSecureServer = (function() {
             }).then(function(response) {
                 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        : "GET",