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=eae32193e9&notice_str=6945815118&hash=f658cb1b99ab6508b1d5ac61efb92f92&redirect_to=https%3A%2F%2Fu.limo%2Ftag%2Fvhs%25E8%2580%2581%25E7%2594%25B5%25E5%25BD%25B1%2F' caused an error:

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