Not all games support the option of cloud saves. For example, the demo and trial versions of games (by default) do not support this function. Moreover, some games should preliminarily be checked in the gaming platforms (e.g. Steam, Origin) on the availability of this function.
For example, the game Just Cause 3 lacks the option to save in-game progress in the cloud. You can review this forum page where this information is being discussed.
You can enable cloud saves for all games that support this function (e.g. for the Steam platform). Click > Steam > Settings > Cloud and check the box.
We never store users' data, therefore, offline saves would exist till the session is terminated. If the problem with cloud sync happens when you launch a game on Boosteroid, we are not able to help you here.
In case the "Cloud Sync Conflict" did happen, you need to choose the first option
"download to this machine".
When there is a temporary disruption in the work of the gaming platform (e.g. Steam, Origin, etc.) cloud synchronization may not happen at once. In this situation, it is suggested to wait for a while and not terminate the session (the browser tab) since when it is already closed - the cloud synchronization will not be completed.
For more information, please review this article (for the Steam games). Where all situations and solutions on the topic of the "Steam cloud " are provided.
Moreover, you can always manually check the status of the servers by following this link - https://downdetector.com/. Write down the name of the platform or game in question (e.g. Epic Games Store or separately Fortnite) and you will be shown with the current status of any particular game or the gaming platform as the whole.