The feature will be unavailable for a short while.
As we’re preparing for the public launch of GOG Galaxy 1.2 we need to perform maintenance work on the GOG Galaxy Cloud Saves backend. The servers will go down on Wednesday, April 19th early morning UTC and will remain offline for the rest of the day. You will still have access to the local copy of your save files, and any new files you create will be synced to the cloud automatically once the maintenance is done. During the maintenance, the GOG Galaxy app may report failure while syncing the cloud saves.
Apologies for any inconvenience.