diff --git a/flatpak-proxy.c b/flatpak-proxy.c
index 2ea079c..eab7a89 100644
--- a/flatpak-proxy.c
+++ b/flatpak-proxy.c
@@ -1166,6 +1166,24 @@ header_free (Header *header)
   g_free (header);
 }
 
+static const char *
+header_debug_str (GString *s, Header *header)
+{
+  if (header->path)
+    g_string_append_printf (s, "\n\tPath: %s", header->path);
+  if (header->interface)
+    g_string_append_printf (s, "\n\tInterface: %s", header->interface);
+  if (header->member)
+    g_string_append_printf (s, "\n\tMember: %s", header->member);
+  if (header->error_name)
+    g_string_append_printf (s, "\n\tError name: %s", header->error_name);
+  if (header->destination)
+    g_string_append_printf (s, "\n\tDestination: %s", header->destination);
+  if (header->sender)
+    g_string_append_printf (s, "\n\tSender: %s", header->sender);
+  return s->str;
+}
+
 static Header *
 parse_header (Buffer *buffer, guint32 serial_offset, guint32 reply_serial_offset, guint32 hello_serial, GError **error)
 {
@@ -1175,6 +1193,7 @@ parse_header (Buffer *buffer, guint32 serial_offset, guint32 reply_serial_offset
   guint32 reply_serial_pos = 0;
   const char *signature;
   g_autoptr(GError) str_error = NULL;
+  g_autoptr(GString) header_str = NULL;
 
   g_autoptr(Header) header = g_new0 (Header, 1);
 
@@ -1296,10 +1315,13 @@ parse_header (Buffer *buffer, guint32 serial_offset, guint32 reply_serial_offset
           header->path = get_string (buffer, header, &offset, end_offset, &str_error);
           if (header->path == NULL)
             {
+              header_str = g_string_new (NULL);
               g_set_error (error,
                            G_IO_ERROR,
                            G_IO_ERROR_INVALID_DATA,
-                           "Could not parse path in path field: %s", str_error->message);
+                           "Could not parse path in path field: %s%s",
+                           str_error->message,
+                           header_debug_str (header_str, header));
               return NULL;
             }
           break;
@@ -1316,10 +1338,13 @@ parse_header (Buffer *buffer, guint32 serial_offset, guint32 reply_serial_offset
           header->interface = get_string (buffer, header, &offset, end_offset, &str_error);
           if (header->interface == NULL)
             {
+              header_str = g_string_new (NULL);
               g_set_error (error,
                            G_IO_ERROR,
                            G_IO_ERROR_INVALID_DATA,
-                           "Could not parse interface in interface field: %s", str_error->message);
+                           "Could not parse interface in interface field: %s%s",
+                           str_error->message,
+                           header_debug_str (header_str, header));
               return NULL;
             }
           break;
@@ -1336,10 +1361,13 @@ parse_header (Buffer *buffer, guint32 serial_offset, guint32 reply_serial_offset
           header->member = get_string (buffer, header, &offset, end_offset, &str_error);
           if (header->member == NULL)
             {
+              header_str = g_string_new (NULL);
               g_set_error (error,
                            G_IO_ERROR,
                            G_IO_ERROR_INVALID_DATA,
-                           "Could not parse member in member field: %s", str_error->message);
+                           "Could not parse member in member field: %s%s",
+                           str_error->message,
+                           header_debug_str (header_str, header));
               return NULL;
             }
           break;
@@ -1356,10 +1384,13 @@ parse_header (Buffer *buffer, guint32 serial_offset, guint32 reply_serial_offset
           header->error_name = get_string (buffer, header, &offset, end_offset, &str_error);
           if (header->error_name == NULL)
             {
+              header_str = g_string_new (NULL);
               g_set_error (error,
                            G_IO_ERROR,
                            G_IO_ERROR_INVALID_DATA,
-                           "Could not parse error in error field: %s", str_error->message);
+                           "Could not parse error in error field: %s%s",
+                           str_error->message,
+                           header_debug_str (header_str, header));
               return NULL;
             }
           break;
@@ -1392,10 +1423,13 @@ parse_header (Buffer *buffer, guint32 serial_offset, guint32 reply_serial_offset
           header->destination = get_string (buffer, header, &offset, end_offset, &str_error);
           if (header->destination == NULL)
             {
+              header_str = g_string_new (NULL);
               g_set_error (error,
                            G_IO_ERROR,
                            G_IO_ERROR_INVALID_DATA,
-                           "Could not parse destination in destination field: %s", str_error->message);
+                           "Could not parse destination in destination field: %s%s",
+                           str_error->message,
+                           header_debug_str (header_str, header));
               return NULL;
             }
           break;
@@ -1412,10 +1446,13 @@ parse_header (Buffer *buffer, guint32 serial_offset, guint32 reply_serial_offset
           header->sender = get_string (buffer, header, &offset, end_offset, &str_error);
           if (header->sender == NULL)
             {
+              header_str = g_string_new (NULL);
               g_set_error (error,
                            G_IO_ERROR,
                            G_IO_ERROR_INVALID_DATA,
-                           "Could not parse sender in sender field: %s", str_error->message);
+                           "Could not parse sender in sender field: %s%s",
+                           str_error->message,
+                           header_debug_str (header_str, header));
               return NULL;
             }
           break;
@@ -1469,10 +1506,12 @@ parse_header (Buffer *buffer, guint32 serial_offset, guint32 reply_serial_offset
     case G_DBUS_MESSAGE_TYPE_METHOD_CALL:
       if (header->path == NULL || header->member == NULL)
         {
+          header_str = g_string_new (NULL);
           g_set_error (error,
                        G_IO_ERROR,
                        G_IO_ERROR_INVALID_DATA,
-                       "Method call is missing path or member");
+                       "Method call is missing path or member%s",
+                       header_debug_str (header_str, header));
           return NULL;
         }
       break;
@@ -1480,10 +1519,12 @@ parse_header (Buffer *buffer, guint32 serial_offset, guint32 reply_serial_offset
     case G_DBUS_MESSAGE_TYPE_METHOD_RETURN:
       if (!header->has_reply_serial)
         {
+          header_str = g_string_new (NULL);
           g_set_error (error,
                        G_IO_ERROR,
                        G_IO_ERROR_INVALID_DATA,
-                       "Method return has no reply serial");
+                       "Method return has no reply serial%s",
+                       header_debug_str (header_str, header));
           return NULL;
         }
       break;
@@ -1491,10 +1532,12 @@ parse_header (Buffer *buffer, guint32 serial_offset, guint32 reply_serial_offset
     case G_DBUS_MESSAGE_TYPE_ERROR:
       if (header->error_name  == NULL || !header->has_reply_serial)
         {
+          header_str = g_string_new (NULL);
           g_set_error (error,
                        G_IO_ERROR,
                        G_IO_ERROR_INVALID_DATA,
-                       "Error is missing error name or reply serial");
+                       "Error is missing error name or reply serial%s",
+                       header_debug_str (header_str, header));
           return NULL;
         }
       break;
@@ -1504,30 +1547,36 @@ parse_header (Buffer *buffer, guint32 serial_offset, guint32 reply_serial_offset
           header->interface == NULL ||
           header->member == NULL)
         {
+          header_str = g_string_new (NULL);
           g_set_error (error,
                        G_IO_ERROR,
                        G_IO_ERROR_INVALID_DATA,
-                       "Signal is missing path, interface or member");
+                       "Signal is missing path, interface or member%s",
+                       header_debug_str (header_str, header));
           return NULL;
         }
       if (strcmp (header->path, "/org/freedesktop/DBus/Local") == 0 ||
           strcmp (header->interface, "org.freedesktop.DBus.Local") == 0)
         {
+          header_str = g_string_new (NULL);
           g_set_error (error,
                        G_IO_ERROR,
                        G_IO_ERROR_INVALID_DATA,
-                       "Signal is to D-Bus Local path or interface (%s, %s)",
-                       header->path, header->interface);
+                       "Signal is to D-Bus Local path or interface%s",
+                       header_debug_str (header_str, header));
           return NULL;
         }
       break;
 
     default:
       /* Unknown message type, for safety, fail parse */
+      header_str = g_string_new (NULL);
       g_set_error (error,
                    G_IO_ERROR,
                    G_IO_ERROR_INVALID_DATA,
-                   "Unknown message type (%d)", header->type);
+                   "Unknown message type (%d)%s",
+                   header->type,
+                   header_debug_str (header_str, header));
       return NULL;
     }