In the recent 184.108.40.206 release of Magento, they introduced a bug which affected the XML-RPC service. Remarkety uses this service to retrieve recent information about the store's shoppers, products and orders.
If you currently have this exact version installed, Remarkety will not be able to synchronize with your store.
Magento recently released a version which addresses this problem and several more (release notes here). We have verified that stores upgrading to the 220.127.116.11 version can once again sync successfully.
We therefore advise you, if you've installed the 18.104.22.168 version, to upgrade as soon as possible to the 22.214.171.124, and check that Remarkety is synching with your store.