Invalid Token message on Login

Question

While logging in the jomsocial or joomla administration page, an "invalid tokken" error is shown first ... then after two three page refreshes it gets cleared. Have once installe a custom plugin and later uninstalled it.. After that these problem arrived.....

Should there be any change in configuration file configuration.php

class JConfig {
public $offline = '0';
  //other lines regards to the site details hence not pasted..
   public $MetaTitle = '0';
public $MetaAuthor = '0';
public $sef = '1';
public $sef_rewrite = '1';
public $sef_suffix = '1';
public $unicodeslugs = '0';
public $feed_limit = '10';

    public $lifetime = '15';
public $session_handler = 'database';
public $MetaRights = '';
public $sitename_pagetitles = '0';
public $force_ssl = '0';
public $feed_email = 'site';
public $cookie_domain = '';
public $cookie_path = '';

or is it regarded to some modification in default.php

Answer 1

The "System - Cache" plugin is often responsible for this issue, as the login form attempts to create a unique token on each page, and that plugin takes a snapshot of a page after it has been processed, and will deliver it unmodified to the end user. If that plugin is enabled, disable it.

Also, if you are getting these issues in the Joomla backend, it is possible that you are using an Apache cache module. Ask your system administrator to disable mod_cache if it's enabled.

Answer 2

Well,Its probably because of cache created by module. Try clearing all the cookies and cache of the browser and try again. If problem perist try disabling the cache of the newly installed module/plugin.Its better not to login using the same id from both frontend and backend .