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=bf59a9707a&notice_str=0078053179&hash=12b962a13d0f9b3a1b4f2e1a6eb7a252&redirect_to=https%3A%2F%2Fu.limo%2F14139%2F' caused an error:

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