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=68232355da&notice_str=0528320610&hash=cb0d183dbb8ac74c9fd8fb41a2a049be&redirect_to=https%3A%2F%2Fu.limo%2F14017%2F' caused an error:

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