Error: 404 Not Found

Sorry, the requested URL 'http://u.limo/wp-admin/admin-ajax.php?channel_id=social_wechat&action=xh_social_channel&tab=login_redirect_to_authorization_uri&xh_social_channel=7599b3c128&notice_str=7233154409&hash=e499f572e559cdfdc346872db07ac861&redirect_to=https%3A%2F%2Fu.limo%2Ftag%2F%25E6%25AD%25A3%25E6%2596%25B9%25E5%25B1%258F%2F' caused an error:

Not found: '/wp-admin/admin-ajax.php'