Bump stanza timeouts from 20s to 60s.

src/headless/plugins/mam/plugin.js

@@ -32,7 +32,7 @@ converse.plugins.add('converse-mam', {
             mam_request_all_pages: true,
             message_archiving: undefined, // Supported values are 'always', 'never', 'roster'
                                           // https://xmpp.org/extensions/xep-0313.html#prefs
-            message_archiving_timeout: 20000 // Time (in milliseconds) to wait before aborting MAM request
+            message_archiving_timeout: 60000 // Time (in milliseconds) to wait before aborting MAM request
         });
 
         Object.assign(api, mam_api);

src/headless/shared/settings/constants.js

@@ -102,7 +102,7 @@ export const DEFAULT_SETTINGS = {
     sid: undefined,
     singleton: false,
     strict_plugin_dependencies: false,
-    stanza_timeout: 20000,
+    stanza_timeout: 60000,
     view_mode: 'overlayed', // Choices are 'overlayed', 'fullscreen', 'mobile'
     websocket_url: undefined,
     whitelisted_plugins: [],