This issue has been noticed on iOS devices that have a device name created that contains emojis (specifically 4-byte utf8 emojis).
If you see the message "Failed to synchronise network to Cloud" appear but believe that you have reliable Bluetooth connection to your network and also reliable Internet connection, the reason may be due to using a character in the Casambi app that cannot be correctly encoded to the Casambi cloud service.
This would most likely on characters used for the name of the network. A work around is to go to the device Settings/General/About/Name and then change the name to one that uses Latin or alphabetical characters.
Casambi are checking options to see if there are possibilities in future for encoding of other characters too.